Author: Keith Evans
Date: 12:04:58 04/28/03
Go up one level in this thread
On April 27, 2003 at 10:40:10, Aaron Gordon wrote: >On April 27, 2003 at 01:52:41, Keith Evans wrote: > >>On April 27, 2003 at 01:38:15, Aaron Gordon wrote: >> >>>On April 26, 2003 at 22:52:42, Keith Evans wrote: >>> >>>>On April 26, 2003 at 22:25:47, Aaron Gordon wrote: >>>> >>>>>On April 26, 2003 at 21:11:59, Tom Kerrigan wrote: >>>>> >>>>>>I checked Aaron's story with his contact at AMD. The guy said that AMD didn't >>>>>>allow performance testing with the memory _overclocked_, but it certainly isn't >>>>>>underclocked. This makes perfect sense to me. (If you allow overclocking memory, >>>>>>why wouldn't you also overclock the processor? Then all your benchmarks are >>>>>>worthless.) >>>>>> >>>>>>So SPEC is comparing non-overclocked Intel to non-overclocked AMD and Intel >>>>>>wins. >>>>>> >>>>>>-Tom >>>>> >>>>>When I ran the tests I recalled seeing some information where the P4 was running >>>>>CAS2 and the like. The settings I was told to use put me at CAS 2.5. >>>>>How would this be 'fair'? Same thing happens on some review pages, but to a much >>>>>larger degree. As I have proven in the past tomshardware has actually run the >>>>>memory lower than the bus on the athlons tested, put the AGP to 1x, etc. >>>>> >>>>>Also, running CAS2 with all tweaks enabled isn't "overclocking". Especially when >>>> >>>>I think that the main point is that the manager basically was trying to prevent >>>>memory (and maybe other components) from being run out of specification. This is >>>>what I suspected. He probably felt that if AMD ran components out of spec and >>>>quoted the numbers, then Intel could get nasty. >>>> >>>>Your argument is with him. Determining that memory is being run in spec is not >>>>as simple as quoting a single parameter like "CAS 2.5." Download a memory >>>>datasheet, a chipset datasheet, see how the BIOS is programming the chipset, >>>>draw waveforms, and check all of the parameters. It is painful, but anything >>>>else is handwaving. >>> >>>What I'm trying to point out is the ram was Corsair PC2400XMS CL2. Rated for >>>150MHz(300DDR) at CL2.0. I was told to run 133MHz fsb stock (which I have no >>>problems with) and CL2.5, bank interleaving off, other timings slower than usual >>>which IS much below the rams normal speed. >>> >>>Nothing was overclocked, nothing would have been overclocked. Even with maximum >>>timings, the ram would be still running UNDER spec. If you'd like to see for >>>yourself, here is the PC2400XMS CL2 datasheet from Corsair. >>> >>>http://www.corsairmicro.com/main/products/specs/cm64sd256.pdf >>> >>>The numbers off of the dimm = CM64SD256-2400C2 >>> >>>If for some reason you'd like to see the DIMM, go here.. >>>http://www.newageoc.com/pics2/corsair2400cl2.jpg >> >>Then the question remains, why did the manager apparently believe that something >>would be operating out of spec? That corsair datasheet doesn't have enough >>detail. See page 50 and associated diagrams in the following: >> >>http://download.micron.com/pdf/datasheets/dram/128Mx4x8x16DDR_D.pdf >> >>Regards, >>Keith > >Running 150MHz CL2 ram at 133MHz CL2 isn't going to put it out of spec. Looking at the JPEG that you posted it looks like the part number for the Micron DDR SDRAM is 46V16M8-75B. Without any "Z" after the "75". That part is not rated for 133 MHz CL2 operation, you need to run it with CL=2.5 for 133 MHz. If you want CL=2 then lower the frequency to 100 MHz. This is from the cover sheet of the Micron specification which I posted. If there is a "Z" on the package after the "75" that I missed, then I agree with you. Regards, Keith
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