Which AMD processor? 500w is fine to use for an example, but in all
practicality you're not going to draw 500w from the wall.. nevermind use
that much (on the low voltage side of the PSU) on a routing box. My dual
core brisbane, complete with GTX-260 video card and multiple SATA 7200RPM
hard drives doesn't even use 500w at max load.. and I've run plenty of
Palomino/Tbred-Bs off el-cheapo 300w powersupplies which would surely burn
out if I even approached a 300w load - and that was with Radeon
9600/9800Pros.
I'm assuming this is a Socket 754/939/AM2 CPU, so you can run CnQ with the
K8/Opteron or ACPI CPU power saving drivers.. which would mean that your box
should idle at 800-1000MHz with a reduced Vcore and use very little power.
You can have it auto ramp up the CPU clock under load with 'ondemand'
powersaving, or even run it statically at your minimum HT frequency (800 or
1000MHz). Get a SMALL PSU if you want to save power, they'll have greater
efficiency at the lower loads - even the 85% PSUs are pretty inefficient if
you're using a 500w powersupply but only drawing 150w. That's a pretty
minimal investment for some increased efficiency.There is an efficiency
curve, it is not 85% efficient at all power levels.
I'd use a USB flash drive for the OS, you'll save a little bit of power
there and it's a very small investment as well - on the plus side, it's also
silent and cool! 8gb should be more than enough, but if you want to have
lots of room for your web cache you could RAID0 two or three 8gb flash
drives. I'm not a fan of using older hard drives, but I can't talk much - I
still have several 120GB Western Digital JB/BB drives 'in service' for my
own PCs.
-Frank
----- Original Message -----
From: "Chris Knadle" <[email protected]>
To: <[email protected]>
Sent: Tuesday, May 26, 2009 9:59 PM
Subject: Re: [mhvlug] Network Routing question
On Tuesday 26 May 2009, Joseph Apuzzo wrote:
No just wanted to do the routing on a Linux box, along with DHCP
NTP and other services. I was going to keep the WRT56G to do all
the wireless and such. Wanted to get full firewall and Web cache
going to max out my Internet since my employer no longer pays for
it.
That's all very do-able; if you're only looking for the router to take
care of wired connections then it's a lot easier.
Power is a point it will take more power but the equipment is free
( new power friendly equipment will cost upwards of $300 ) so power
savings does not cover the cost.
Okay, let me put it another way.
Let's say you pay 16 cents/kWh for power at home.
Let's just say you know your old 2 GHz AMD Desktop box uses 500 Watts.
And you're going to run that 24/7 because it's a router.
That's 24 h * .5 kW = 12 kWh per day.
12 kWh * $.16 = about $2 / day, or nearly $60 a month.
Which means that the ROI (return-on-investment) of $300 worth of
equipment that runs at low power would pay for itself in 5 months.
You can look up specs for the amount of power the CPU, fans, and hard
disk uses, and that can give you a very rough guess as to the minimum
power the box might use; this plus looking up what you pay per kWh on
your power bill and you can re-check what running it as your FW will
cost you.
Power cost was NOT the reason I went to low-power boxes, by the way.
Old hard drives, power supplies, and fans are all reliability
problems. A low power box with no moving parts that only needs
passive cooling is a godsend.
I guess what need answered is how much power does the system take
while idling. How would I measure that?
A Watt meter. There's a more complicated way of considering the
situation if you want to take Power Factor into account, but the good
news is that you don't need to worry about that because you only
actually pay for what a Watt meter reads, even though the power
company has to actually supply you a bit more than that due to Power
Factor considerations.
-- Chris
--
Chris Knadle
[email protected]
_______________________________________________
Mid-Hudson Valley Linux Users Group http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug
Upcoming Meetings (6pm - 8pm) MHVLS Auditorium
Jun 3 - TBD
Jul 1 - TBD
Aug 5 - TBD
_______________________________________________
Mid-Hudson Valley Linux Users Group http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug
Upcoming Meetings (6pm - 8pm) MHVLS Auditorium
Jun 3 - TBD
Jul 1 - TBD
Aug 5 - TBD
