Author: Aaron Gordon
Date: 16:47:57 04/28/03
Go up one level in this thread
On April 28, 2003 at 15:04:58, Keith Evans wrote: >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 So Corsair is selling overclocked ram? The ram itself is rated by Corsair for 150MHz opteration at CAS-2.0. It runs 166MHz CAS-2.0 (but I consider THAT overclocking, not 150MHz CAS-2.0). 133MHz CAS-2.5 would be extreme underclocking. It wasn't rated PC2400 CL2 for nothing.
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