>From: [EMAIL PROTECTED] (flawed jai) >Date: Thu, 13 Mar 2003 04:06:46 -0800 (PST)
>KOG <[EMAIL PROTECTED]> >and KOG replied: >This is a good question. I bought a Umax 250Mhz card on ebay and paid a >premium for it. I just tried it the other night and low and behold this >250 Mhz card shows up as a 200 Mhz one. I contacted the vendor and they >are sending me another one. If that one doesn't go any faster than the >last one they gave me, I'll give up on non G3 or better upgrade cards. >KOG >----------------- > >you should be aware that bus speed limits the maximum processor speed >you can acheive with trying for a G3 upgrade. >only macs with bus speeds of 50 can get full use out of processor >upgrade chips clocked at multiples of 50. if your bus speed is 40, you >are not gonna be able to get the full maximum speed implied in the >chip's name. <snipped a bunch of carefully written explanation based on an incorrect first premise> >so the guys you bought it from might be perfectly honest, and the chip >probably DOES do 250Mhz, but only on a 50 Mhz bus. the problem might be >your bus speed. it can't be upgraded and you can't get any more >acceleration out of it. The bus speed in the x500 series of machines, such as use the Umax processor cards, is set by the CPU card, not by the motherboard. If you try to install a card with a bus speed set higher than the motherboard can tolerate, the machine simply won't work; the CPU card will not be reset to a lower bus speed. This is different than the situation where one is installing a PDS G3 upgrade in an x100 machine. So the card they sent Keven is either a 250 or it is not. However, I would question whether the utility Kevin used to measure it's speed is accurate. Apple System Profiler is notorious for being wrong a lot of the time. Try Clockometer from NewerTech for more accurate readings. To elaborate a bit on the first paragraph....CPU cards for the x500 machines supply all the bus clocks to the motherboard (through pins 9 through 14). So there's an oscillator on the CPU card which is built to run somewhere between 40 and 50 MHz and sometimes adjustable above that on third party upgrade cards. Then they have a bus multiplier as well. So, if you buy a 250 MHz CPU card, it presumably has a 50 MHz oscillator setting the bus speed and the CPU is set to a 5X multiplier. It's possible that the seller sold you a 200 MHz Umax card which has a 50 MHz oscillator and a 4X multiplier. It is not possible that the bus speed of the card magically changed from 50 MHz to 40 MHz. There's a little component soldered down which is labeled 50 MHz on the Umax card and that just doesn't change without the application of heat and solder. On the Umax cards the speed of the CPU card is usually silkscreened near one end of the card on the flat back (opposite the heat sink) surface. The Umax cards work great in Apple machines as they are built to Apple specs., except for the little cable connector at the top of the multiprocessor capable cards. That cable connector can get in the way physically in some models of Apple machines. The primary processor is a different card from the secondary processor in Umax's dual processor scheme. The primary processor works fine alone as a CPU card in Apple or Umax machines. The secondary card can only be used in conjunction with one of the primary cards in a Umax S900 which has two CPU slots. It might be possible to get the secondary card to work as a stand-alone CPU, but it would face the wrong way, so the heat sink would likely cause problems. Note that because the Umax cards are built to Apple specs., they will not work in the Catalyst based Power Computing clones, though they will work in the PTP and PowerWave. Jeff Walther -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
