RJK
Tue Jun 17 07:57:47 PDT 2008
Huge thanks,
...eventually noticed, in CPUZ that my i865PE based mobo/D935cpu | bios
"Auto" option was stubbornly setting FSB at 133mhz !!!,
...have now forced that to 200mhz in bios and CPUZ now reports fsb at
199.7mhz,
and fsb:dram ratio at 1:1 ...where it should have been - instead of 4:3 or
3:2 ...whatever it was,
etc, ....what fun ! ...in a minute or two I shall have a blue screen -
...I can feel it coming my way !
...do you think that I have matched up the labels correctly ? :-
i.e. am attempting to match CPUZ SPD info with my bios options,
..as below:-
tCL = DRAM CAS# Latency 2.0
tRP = DRAM RAS# Precharge 2
tRCD = DRAM RAS# to CAS# Delay 3
tRAS = DRAM Precharge Delay 6
? DRAM Burst Length 4
http://www.rambus.com/us/patents/innovations/detail/variable_burst.html
...now I have to choose between 4 and 8 !!!
regards, Richard
"Paul" <nospam@needed.com> wrote in message news:g38faq$nj3$1@aioe.org...
> RJK wrote:
>> I just bought 2x512 ddr400/pc2300 Corsair XMS 3200LL modules, and after
>> doing quite a bit
>> of Googling,
>> I am no further forward in determing the "best" settings in bios, and
>> indeed, my bios has slightly ambiguous labels which are hard to match up
>> with,
>> tRCD, tRP and tRAS etc.
>>
http://www.techpowerup.com/articles/overclocking/64
>> i.e Which one is which ?
>>
>> If I set bios to use SPD, Lavalys Everest "motherboard" ICH5 reports :-
>> Memory Timings:
>> CAS Latency (CL) 2T
>> RAS To CAS Delay (tRCD) 2T
>> RAS Precharge (tRP) 2T
>> RAS Active Time (tRAS) 5T
>> ???
>>
>> I've just set manually in bios:- (Below is how the bios memory setting
>> options appear on screen btw),
>> DRAM CAS# Latency 2.5
>> DRAM RAS# Precharge 3
>> DRAM RAS# to CAS# Delay 3
>> DRAM Precharge Delay 5
>> DRAM Burst Length 4
>> ...and CPUZ reflects these settings accurately, ...(dunno what Lavalys
>> Everest is doing ?!)
>> anyhooo...
>> ...completely confused, after reading lots about setting CAS to 2 can not
>> be as "good" as setting it to 2.5 ???
>>
>> ...any advice much appreciated,
>>
>> TIA
>>
>> regards, Richard
>>
>
> CAS affects the latency. Lower CAS is better. 2 is better than 2.5 .
>
> Corsair products tend to have datasheets. If you look hard enough,
> you can find the exact one for your RAM. I'm not sure whether this
> is yours or not (need the full part number).
>
>
http://www.corsairmicro.com/_datasheets/twinx1024-3200ll.pdf
>
> CPUZ from cpuid.com, displays two things. In the "SPD" tab, you
> can see the values recorded in the SPD chip on the DIMM. That
> may or may not reflect what the memory is actually capable of.
> And will help you understand what the BIOS will do, when the
> BIOS is set to use SPD. You compare the CPUZ SPD values to the
> datasheet values, to see whether the SPD actually contains the
> correct data. On some RAM, slower settings are used in the SPD,
> to guarantee that the motherboard will POST - then the user
> sets things manually, to the datasheet values.
>
> The CPUZ "Memory" tab, shows the current choices for Tcl, Trcd, Trp, Tras.
> So you can see what settings actually resulted.
>
> When you see 2,3,2,5 in the datasheet, the order is "CAS Latency, tRCD,
> tRP, tRAS",
> the same as in CPUZ.
>
> I hope that answers your question.
>
> Paul