Re: AMD power reduction
Le lundi 08 fivrier 2010 04:10:22, Nick Holland a icrit : With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. Hello, I did. It's consuming some 90 Watts at idle. Actually, it's an Athlon but the latest Sempron has an even reduced TDP. My next server will be based on it. Actually even 70 Watts is a little bit high for my next server given the fact it will be in an autonomous environment (small wind/solar generators). Regards
Re: AMD power reduction
From: Jean-Francois [mailto:jfsimon1...@gmail.com] Le lundi 08 fivrier 2010 04:10:22, Nick Holland a icrit : With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. Hello, I did. It's consuming some 90 Watts at idle. Actually, it's an Athlon but the latest Sempron has an even reduced TDP. My next server will be based on it. Actually even 70 Watts is a little bit high for my next server given the fact it will be in an autonomous environment (small wind/solar generators). Regards Nick is right, numbers should speak. Parameters at the time of measuring: MB: GA-MA74GM-S2H rev1.x (no idea about TDP but according to [1] should be low) - unneeded MB components turned off, check my previous dmesg - integrated GPU core slowed down from 400MHz to 200MHz - Cool'n'quiet enabled in BIOS CPU: AMD Sempron LE-1150 (TDP 45W) - undervolted from 1.2V to 1.00V - passive cooling PSU: Enermax 400W Liberty (no data for this model but it's bigger brothers had efficiency around 78% for 114W AC [2]) RAM: 1 stick of 1GB DDR2 800MHz HDD: 3x 1TB, 2x 500G (4 Hitachi and 1 WD Green) other: 1 low rpm 12cm system fan, no keyboard, no display I measured my setup couple of times while setting it up. Numbers are from memory, may not be accurate. Besides, I used a cheap powermeter, meaning the absolute values are probably off but the deltas could be somewhat trusted: 1. On boot with everything on and no udervolting of CPU the AC wattage was somewhere around 150W. 2. Undervolting the CPU to 1.00V and playing with the BIOS shaved off some 20-30W. 3. Setting the Hitachi drives to low power idle reduced the power draw for another 20-30W, at the time the system was idling at 70-90W. 4. Putting the drives into sleep mode got the system under 70W. I'm not using this atm, had some problems with long delays while waking up the drives. All of that was without apm -C, basically the CPU was running at full speed. For testing apm -C I was lazy and relied on temperatures. 1. Temperatures at idle with apm -C hw.sensors.it0.temp0=28.00 degC hw.sensors.it0.temp1=33.00 degC 2. Temperatures at idle with apm -H (from memory and different season) hw.sensors.it0.temp0=34.00 degC hw.sensors.it0.temp1=38.00 degC Couple of degrees difference should mean at least couple of W difference. Regards, Daniel. Useful links: 47 watt 7 TB server (disks spun down) - http://www.silentpcreview.com/forums/viewtopic.php?t=57476 TDP list for Intel chipsets - http://www.silentpcreview.com/forums/viewtopic.php?t=35078 [1] http://www.silentpcreview.com/article859-page5.html [2] http://www.silentpcreview.com/article279-page4.html
Re: AMD power reduction
Le lundi 08 fivrier 2010 10:41:18, Daniel Gracia Garallar a icrit : If absolute raw power is not mandatory, you may have a look at Atom-based servers -like http://www.supermicro.es/?opcion=contenidoplt=notasid=137 for example-. This servers consumption should make a difference when working on renovable energy sources. Regards! Jean-Francois escribis: Le lundi 08 fivrier 2010 04:10:22, Nick Holland a icrit : With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. Hello, I did. It's consuming some 90 Watts at idle. Actually, it's an Athlon but the latest Sempron has an even reduced TDP. My next server will be based on it. Actually even 70 Watts is a little bit high for my next server given the fact it will be in an autonomous environment (small wind/solar generators). Regards Thank you for this information. Is it working ok with OpenBSD ? Standard x86 is suitable ? Regards.
Re: AMD power reduction
Le lundi 08 fivrier 2010 10:41:18, Daniel Gracia Garallar a icrit : If absolute raw power is not mandatory, you may have a look at Atom-based servers -like http://www.supermicro.es/?opcion=contenidoplt=notasid=137 for example-. those work ok (i386/amd64 kernels). you must use a 2.5 drive if you want to use the PCIE slot (get the 1x2.5 carrier, not the dual one, if you want that), and note that the PCI slots aren't usable in that chassis. supermicro also have some newer mini-itx Atom boards - ICH9: more sata, em(4), optional IPMI - and there are also numerous low-power systems from a range of manufacturers using various CPUs (VIA, Geode, EP80579, Atom, ..). if you don't need i386 compatibility, keep an eye on OpenBSD/loongson too. (or OpenBSD/armish but the supported hardware doesn't seem to be available new any more, the closest replacement for Thecus N2100 uses a different CPU [still arm-based, but this time a slower Oxford Semiconductor one rather than the XScale]). but without more information on what server means to you, it's hard to say what might actually be suitable...
Re: AMD power reduction
If absolute raw power is not mandatory, you may have a look at Atom-based servers -like http://www.supermicro.es/?opcion=contenidoplt=notasid=137 for example-. This servers consumption should make a difference when working on renovable energy sources. Regards! Jean-Francois escribis: Le lundi 08 fivrier 2010 04:10:22, Nick Holland a icrit : With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. Hello, I did. It's consuming some 90 Watts at idle. Actually, it's an Athlon but the latest Sempron has an even reduced TDP. My next server will be based on it. Actually even 70 Watts is a little bit high for my next server given the fact it will be in an autonomous environment (small wind/solar generators). Regards
Re: AMD power reduction
Le vendredi 05 fivrier 2010 17:51:05, Calomel Org a icrit : You can use apm. It will only save a few watts, but it may reduce the cooling costs by reducing the heat generated by the CPU. If you have _many_ machines you can easily reduce the temperature of the server room by a few degrees C. Is there something one can do to make the system fall into sleep in OpenBSD ? Thank you.
Re: AMD power reduction
On Sun, 7 Feb 2010 18:44:13 +0100 Jean-Francois jfsimon1...@gmail.com wrote: Is there something one can do to make the system fall into sleep in OpenBSD ? Suspending has worked for some time on OpenBSD. Have a look at: zzz But you might want to do your homework about the wakeing up part.
Re: AMD power reduction
hmm, on Sun, Feb 07, 2010 at 07:10:29PM +0100, Robert said that On Sun, 7 Feb 2010 18:44:13 +0100 Jean-Francois jfsimon1...@gmail.com wrote: Is there something one can do to make the system fall into sleep in OpenBSD ? Suspending has worked for some time on OpenBSD. Have a look at: zzz But you might want to do your homework about the wakeing up part. if you mean this as general as you wrote it, could you cite your sources? suspend has never worked on any of my machines. or, more precisely, they fall asleep, they just never wake up. -f -- questions, questions! does it ever end?!
Re: AMD power reduction
As far as I can see, any modern processor supports several states C0, C1, ... Is there any way to take advantage of this into OpenBSD in order to reduce the system consumption by falling the CPU in C1 state or higher ? Regards
Re: AMD power reduction
snip Note: When running with the lowest multiplier, HDD I/O performance may suffer. In my case the lowest CPU rate is at 1000MHz and with full I/O load accross 1 or 2 HDDs the CPU load is below the treshold of the apm -C, so it doesn't speed up. If I switch it manually with apm -H the transfer rate doubles. No RAID here so we're speaking about 30MB/s with apm -C vs. 60MB/s for apm -H. Forgot to mention but this is for stuff served over samba meaning there is some network I/O involved also. Hi, Re your answer, from man page APM(8) : -C Set apmd(8) to cool running performance adjustment mode. In this mode, when CPU idle time falls below 10%, apm raises hw.setperf as much as necessary. Otherwise when CPU idle time is above 30%, apm lowers hw.setperf as much as possible to reduce heat, noise, and power consumption. -H Set apmd(8) to manual performance adjustment mode and hw.setperf to 100. I don't understant why you have lower performances after apm -C while in my opinion it should just adjust low / fast in function of the system load requirement ? Are disk IO not consideredas CPU load ? The disk I/O + samba doesn't stress the CPU enough so it does not speed up. Which is good :) I expect my disk I/O to keep CPU usage low, that's why we have all that DMA, I/O controllers and stuff. Bad thing is, with the lowest CPU multiplier, something else is slowed down. Maybe the communication with the southbridge or the CPU gets very ineffective in processing data from the bus or something completly different ... At the moment apm -C is not tunable and in my case with my hardware it is not sensitive enough but I don't care that much since I'm more concerned with power consumption than raw performance. Will it be a problem for you? I have no idea, you should try it with your hardware. Regards, Daniel.
Re: AMD power reduction
The disk I/O + samba doesn't stress the CPU enough so it does not speed up. Which is good :) I expect my disk I/O to keep CPU usage low, that's why we have all that DMA, I/O controllers and stuff. Bad thing is, with the lowest CPU multiplier, something else is slowed down. Maybe the communication with the southbridge or the CPU gets very ineffective in processing data from the bus or something completly different ... At the moment apm -C is not tunable and in my case with my hardware it is not sensitive enough but I don't care that much since I'm more concerned with power consumption than raw performance. Will it be a problem for you? I have no idea, you should try it with your hardware. Regards, Daniel. I have a friend who is going to need very low power consumption. Therefore I'm currently looking into the ways to do so with OpenBSD and more or less dedicated hardware.
Re: AMD power reduction
With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. An ammeter and high school physics V*A=Watts doesn't cut it for AC (in general -- a lot of machines are power-factor corrected now so V*A becomes QUITE useful again, but some have a really big power factor still...just discovered a P4-vintage machine running a power factor of 0.65, which surprised the heck out of me. And if you have no idea what I'm talking about, just get a good Wattmeter that understands real AC Wattage, and don't worry about it). You really need to test assumptions. I'm quite confident a number of you are wasting a lot of time on things that Just Don't Matter in the Big Picture. Twisting the most knobs may not improve things enough to justify the downtime you will see. Spending a lot of money on bizarre hardware may look laughable when you see how little power some vastly superior systems draw. Some slightly older systems which make no attempt to brag about magic power saving technology use very modest amounts of power. Others are gluttonous pigs, of course. Wait until OpenBSD is fully booted (and the system is idle) before worrying about what the meter is showing. Also, look at what your AVERAGE load will be on the system, and be realistic -- most of the time, it will probably be completely idle. I've been quite pleased by the power draw on some PIII-vintage Celeron i810-chipset machines. I haven't got around to putting a full PIII in one to see what it costs for the additional performance. I have theories, but the meter tells. On the other hand, this 1.8GHz P4 with two 80G drives, completely normal mini-tower, is drawing less than 50w (though it is the one with the wicked power-factor -- 75VA). I paid $10 for this machine (yes, great deal), it would take a long time for a Soekris or other specialty machine to save any money for me, IF it could do what I wanted it to. Nick.
Re: AMD power reduction
On 8 February 2010 04:10, Nick Holland n...@holland-consulting.net wrote: With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. An ammeter and high school physics V*A=Watts doesn't cut it for AC (in general -- a lot of machines are power-factor corrected now so V*A becomes QUITE useful again, but some have a really big power factor still...just discovered a P4-vintage machine running a power factor of 0.65, which surprised the heck out of me. And if you have no idea what I'm talking about, just ...go here: http://en.wikipedia.org/wiki/Power_factor
Re: AMD power reduction
On Sun, Feb 07, 2010 at 10:10:22PM -0500, Nick Holland wrote: With all this talk about power reduction...I'm going to toss out one small suggestion: Get a Wattmeter, and measure... Don't waste your time speculating. An ammeter and high school physics V*A=Watts doesn't cut it for AC (in general -- a lot of machines are power-factor corrected now so V*A becomes QUITE useful again, but some have a really big power factor still...just discovered a P4-vintage machine running a power factor of 0.65, which surprised the heck out of me. And if you have no idea what I'm talking about, just get a good Wattmeter that understands real AC Wattage, and don't worry about it). Even though the cheap ones try to measure real power and not apparent power, they are often very inaccurate especially at low loads. Watch out for cheap meters, and if you have multiple similar machines it's not a bad idea to measure them all at once. If you don't believe me, buy two cheap meters of the same kind and one of another kind, if they're within 10% of each other (with a non-resistive load and low power) I suggest you go buy a lottery ticket. They're still useful for relative comparisons, of course. With a machine consuming 100 Watts, switching from a 65% efficient supply (that's an optimistic guess for a cheap power supply a few years ago) to a 80% efficient supply will save 28 watts. If you live in a hot climate and use air conditioning, it's probably worth it in a 24/7 machine. For a machine consuming 50W the savings are probably not worth the investment. If you are buying a new machine, the price difference between a crappy and a good power supply is so small it's a no-brainer. As a bonus the high efficiency supplies run cool and quiet.
Re: AMD power reduction
On Sun, 7 Feb 2010 20:41:31 +0100 frantisek holop min...@obiit.org wrote: hmm, on Sun, Feb 07, 2010 at 07:10:29PM +0100, Robert said that On Sun, 7 Feb 2010 18:44:13 +0100 Jean-Francois jfsimon1...@gmail.com wrote: Is there something one can do to make the system fall into sleep in OpenBSD ? Suspending has worked for some time on OpenBSD. Have a look at: zzz But you might want to do your homework about the wakeing up part. if you mean this as general as you wrote it, could you cite your sources? suspend has never worked on any of my machines. or, more precisely, they fall asleep, they just never wake up. -f You got my point. Exeption are older apm based Thinkpads, like Theo likes to use on flights. And i haven't looked into the recent acpi resume improvements.
Re: AMD power reduction
On 04/02/2010 23:02, Jean-Francois wrote: All, I am looking forward to reduce the TDP for a server planned to be built. As low as possible shall be best, is AMD cool'n quiet operating with latest OpenBSD ? Regards Depending on what you where looking at, you can reduce the voltages (if your BIOS has this much control) and this will lower power/heat. I've done this on PC's with bad HSF in hot temperatures. Though, like over clocking, it's an art that requires testing, trying and patience to find the lowest/highest while still being stable
Re: AMD power reduction
Le vendredi 05 fivrier 2010 11:17:51, vous avez icrit : On 04/02/2010 23:02, Jean-Francois wrote: All, I am looking forward to reduce the TDP for a server planned to be built. As low as possible shall be best, is AMD cool'n quiet operating with latest OpenBSD ? Regards Depending on what you where looking at, you can reduce the voltages (if your BIOS has this much control) and this will lower power/heat. I've done this on PC's with bad HSF in hot temperatures. Though, like over clocking, it's an art that requires testing, trying and patience to find the lowest/highest while still being stable Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards
Re: AMD power reduction
Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards Do you mean change the frequency depending on load on the computer...? This is very easy in a virtual environment, I am not sure on machine. I have seen windows software that allows you to change certain options while in the OS, though weather you could do this in OpenBSD and dynamically you will need to see if someone else knows the answer. GPU's are very easy to do this with...certainly doing it manually, but CPU stuff I'm not so sure...
Re: AMD power reduction
Le vendredi 05 fivrier 2010 17:43:30, vous avez icrit : Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards Do you mean change the frequency depending on load on the computer...? This is very easy in a virtual environment, I am not sure on machine. I have seen windows software that allows you to change certain options while in the OS, though weather you could do this in OpenBSD and dynamically you will need to see if someone else knows the answer. GPU's are very easy to do this with...certainly doing it manually, but CPU stuff I'm not so sure... Ok. I was thinking this is integrated in the core of AMD processor. Anyway I will see depending on the sunked power if it is necessary to reduce it further. Yes, usually the AMD proc use auto reduce of the frequency during standstill of the OS.
Re: AMD power reduction
You can use apm. It will only save a few watts, but it may reduce the cooling costs by reducing the heat generated by the CPU. If you have _many_ machines you can easily reduce the temperature of the server room by a few degrees C. Advanced Power Management control https://calomel.org/apm_control.html -- Calomel @ https://calomel.org Open Source Research and Reference On Fri, Feb 05, 2010 at 11:37:16AM -0500, Jean-Francois wrote: Le vendredi 05 fivrier 2010 11:17:51, vous avez icrit : On 04/02/2010 23:02, Jean-Francois wrote: All, I am looking forward to reduce the TDP for a server planned to be built. As low as possible shall be best, is AMD cool'n quiet operating with latest OpenBSD ? Regards Depending on what you where looking at, you can reduce the voltages (if your BIOS has this much control) and this will lower power/heat. I've done this on PC's with bad HSF in hot temperatures. Though, like over clocking, it's an art that requires testing, trying and patience to find the lowest/highest while still being stable Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards
Re: AMD power reduction
From: Jean-Francois [mailto:jfsimon1...@gmail.com] Sent: Friday, February 05, 2010 5:46 PM Le vendredi 05 fivrier 2010 17:43:30, vous avez icrit : Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards Do you mean change the frequency depending on load on the computer...? This is very easy in a virtual environment, I am not sure on machine. I have seen windows software that allows you to change certain options while in the OS, though weather you could do this in OpenBSD and dynamically you will need to see if someone else knows the answer. GPU's are very easy to do this with...certainly doing it manually, but CPU stuff I'm not so sure... Ok. I was thinking this is integrated in the core of AMD processor. Anyway I will see depending on the sunked power if it is necessary to reduce it further. Yes, usually the AMD proc use auto reduce of the frequency during standstill of the OS. The CPU has the ability to lower it's speed but it's the OS that tells it when to slow down. That's what apm -C tries to do. I'm using this at home to reduce power $$$. I've reduced the CPU voltage, and the speed of the integrated GPU (since it's running headless anyway), put all HDDs on idle timers (IBM/Hitachi drives have some nice powersaving features) and my multi-TB storage is usually consuming below 100W intake. Also, apm -C is pure pleasure and gives a significant reduction with my setup. Note: When running with the lowest multiplier, HDD I/O performance may suffer. In my case the lowest CPU rate is at 1000MHz and with full I/O load accross 1 or 2 HDDs the CPU load is below the treshold of the apm -C, so it doesn't speed up. If I switch it manually with apm -H the transfer rate doubles. No RAID here so we're speaking about 30MB/s with apm -C vs. 60MB/s for apm -H. Forgot to mention but this is for stuff served over samba meaning there is some network I/O involved also. Regards, Daniel. PS dmesg below: OpenBSD 4.6-stable (SQUID_DISKD) #13: Sat Nov 28 14:28:10 CET 2009 r...@pegasus.plan9.homeunix.net:/usr/src/sys/arch/i386/compile/SQUID_DISK D cpu0: AMD Sempron(tm) Processor LE-1150 (AuthenticAMD 686-class, 256KB L2 cache) 2.01 GHz cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUS H,MMX,FXSR,SSE,SSE2,SSE3,CX16 real mem = 1003974656 (957MB) avail mem = 961691648 (917MB) mainbus0 at root bios0 at mainbus0: AT/286+ BIOS, date 02/01/08, BIOS32 rev. 0 @ 0xfb7c0, SMBIOS rev. 2.4 @ 0xf0100 (46 entries) bios0: vendor Award Software International, Inc. version F1 date 02/01/2008 bios0: Gigabyte Technology Co., Ltd. GA-MA74GM-S2H acpi0 at bios0: rev 0 acpi0: tables DSDT FACP SSDT HPET MCFG APIC acpi0: wakeup devices USB0(S3) USB1(S3) USB2(S3) USB3(S3) USB4(S3) USB5(S3) USB6(S3) SBAZ(S4) P2P_(S5) PCE2(S4) PCE3(S4) PCE4(S4) PCE5(S4) PCE6(S4) PCE7(S4) PCE8(S4) PS2K(S5) PCI0(S5) acpitimer0 at acpi0: 3579545 Hz, 32 bits acpihpet0 at acpi0: 14318180 Hz acpimadt0 at acpi0 addr 0xfee0: PC-AT compat cpu0 at mainbus0: apid 0 (boot processor) cpu0: apic clock running at 200MHz ioapic0 at mainbus0: apid 2 pa 0xfec0, version 21, 24 pins ioapic0: misconfigured as apic 4, remapped to apid 2 acpiprt0 at acpi0: bus 0 (PCI0) acpiprt1 at acpi0: bus 4 (P2P_) acpiprt2 at acpi0: bus -1 (PCE2) acpiprt3 at acpi0: bus -1 (PCE3) acpiprt4 at acpi0: bus 2 (PCE4) acpiprt5 at acpi0: bus -1 (PCE5) acpiprt6 at acpi0: bus 3 (PCE6) acpiprt7 at acpi0: bus -1 (PCE7) acpiprt8 at acpi0: bus -1 (PCE8) acpiprt9 at acpi0: bus 1 (AGP_) acpicpu0 at acpi0: PSS acpibtn0 at acpi0: PWRB bios0: ROM list: 0xc/0xd600 0xd/0x1c00 cpu0: PowerNow! K8 2010 MHz: speeds: 2000 1800 1000 MHz pci0 at mainbus0 bus 0: configuration mode 1 (no bios) pchb0 at pci0 dev 0 function 0 ATI RS740 Host rev 0x00 ppb0 at pci0 dev 1 function 0 ATI RS690 PCIE rev 0x00 pci1 at ppb0 bus 1 vga1 at pci1 dev 5 function 0 ATI Radeon 2100 rev 0x00 wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation) wsdisplay0: screen 1-5 added (80x25, vt100 emulation) ppb1 at pci0 dev 4 function 0 vendor ATI, unknown product 0x7914 rev 0x00 pci2 at ppb1 bus 2 re0 at pci2 dev 0 function 0 Realtek 8168 rev 0x01: RTL8168 2 (0x3800), apic 2 int 16 (irq 10), address 00:25:86:e0:22:81 rgephy0 at re0 phy 7: RTL8169S/8110S PHY, rev. 2 ppb2 at pci0 dev 6 function 0 ATI RS690 PCIE rev 0x00 pci3 at ppb2 bus 3 re1 at pci3 dev 0 function 0 Realtek 8168 rev 0x02: RTL8168C/8111C (0x3c00), apic 2 int 18 (irq 7), address 00:1f:d0:5a:41:fa rgephy1 at re1 phy 7: RTL8169S/8110S PHY, rev. 2 ahci0 at pci0 dev 17 function 0 ATI SBx00 SATA rev 0x00: apic 2 int 22 (irq 11), AHCI 1.1 scsibus0 at ahci0: 32 targets sd0 at scsibus0 targ 0 lun 0: ATA, HITACHI HUA7210S, GKAO SCSI3 0/direct fixed sd0: 953868MB, 512 bytes/sec, 1953523055 sec total sd1 at scsibus0 targ 1 lun 0: ATA, HITACHI HUA7210S, GKAO SCSI3 0/direct fixed sd1: 953869MB, 512
Re: AMD power reduction
Le vendredi 05 fivrier 2010 20:07:51, Schvberle Daniel a icrit : From: Jean-Francois [mailto:jfsimon1...@gmail.com] Sent: Friday, February 05, 2010 5:46 PM Le vendredi 05 fivrier 2010 17:43:30, vous avez icrit : Hello, I think of doing this too. What I would like to understand is if I will be able to use the frequency change 1000 / 2000 MHz dynamic load based. Regards Do you mean change the frequency depending on load on the computer...? This is very easy in a virtual environment, I am not sure on machine. I have seen windows software that allows you to change certain options while in the OS, though weather you could do this in OpenBSD and dynamically you will need to see if someone else knows the answer. GPU's are very easy to do this with...certainly doing it manually, but CPU stuff I'm not so sure... Ok. I was thinking this is integrated in the core of AMD processor. Anyway I will see depending on the sunked power if it is necessary to reduce it further. Yes, usually the AMD proc use auto reduce of the frequency during standstill of the OS. The CPU has the ability to lower it's speed but it's the OS that tells it when to slow down. That's what apm -C tries to do. I'm using this at home to reduce power $$$. I've reduced the CPU voltage, and the speed of the integrated GPU (since it's running headless anyway), put all HDDs on idle timers (IBM/Hitachi drives have some nice powersaving features) and my multi-TB storage is usually consuming below 100W intake. Also, apm -C is pure pleasure and gives a significant reduction with my setup. Note: When running with the lowest multiplier, HDD I/O performance may suffer. In my case the lowest CPU rate is at 1000MHz and with full I/O load accross 1 or 2 HDDs the CPU load is below the treshold of the apm -C, so it doesn't speed up. If I switch it manually with apm -H the transfer rate doubles. No RAID here so we're speaking about 30MB/s with apm -C vs. 60MB/s for apm -H. Forgot to mention but this is for stuff served over samba meaning there is some network I/O involved also. Regards, Daniel. Hi, Re your answer, from man page APM(8) : -C Set apmd(8) to cool running performance adjustment mode. In this mode, when CPU idle time falls below 10%, apm raises hw.setperf as much as necessary. Otherwise when CPU idle time is above 30%, apm lowers hw.setperf as much as possible to reduce heat, noise, and power consumption. -H Set apmd(8) to manual performance adjustment mode and hw.setperf to 100. I don't understant why you have lower performances after apm -C while in my opinion it should just adjust low / fast in function of the system load requirement ? Are disk IO not consideredas CPU load ? Regards.
