Getting Memory to run at SPD Settings (PC2100)

[PrinceXizor]

My work computer is a P4-1.7 on a SiS chipset. It has two 512MB modules of PC2100 in it. According to CPU-Z the memory timings are 2.5-3-3-6 which is also the SPD setting at 133Mhz FSB. However, the SPD setting for 100 Mhz FSB is 2-2-2-5. How can I get these timings to run? There are no specific options in the BIOS save for Command Rate and err....cant' remember the other one. Anyway....its a safe, normal, turbo, super fan-tabulitically blazing, etc. kind of list for memory timings.

Thanks!

P-X

 

[3chordcharlie]

The memory is probably running at 133fsb, which is better considering it's a P4; you're probably better off with the extra bandwidth than faster timings.

 

[PrinceXizor]

No, its running at 17x100. The P4 1.7 had a 400Mhz FSB.

P-X

 

[3chordcharlie]

Originally posted by: PrinceXizor
No, its running at 17x100. The P4 1.7 had a 400Mhz FSB.

P-X

Are you sure your m/b doesn't run it out of sync at 133 (many do)?

Otherwise, use the fastest setting on your list of 'safe normal turbo etc'.

 

[PrinceXizor]

How can you be sending a 100Mhz clock signal to your processor and a 133Mhz clock signal to the memory? I know that it can run asynchronously, but I thought that was slightly different in operation. Perhaps I was mistaken, if so....how do I check that, everywhere I look in Sisoft and CPU-Z seems to be showing a 100Mhz FSB.

P-X

 

[LTC8K6]

Running out of synch is entirely normal. The FSB and ram speeds are seperate. Currently my FSB is 133 and my ram is running at 166. Or 533 and 667 in P4 terms. 4:5 FSB to memory ratio.

CPU-Z should report your ram speed as well.

Try WCPUID also.

Memory ratios are available on pretty much all chipsets these days.

 

[PrinceXizor]

Right...I forgot about that.

I proclaim that something is fishy....maybe...

1. CPU-Z does not pull any frequency info for the memory. This is the info I get from CPU-Z.

CAS: 2
RAS to CAS: 2
RAS Pre: 2
TRas: 6
Bank: 9

All other boxes in the timins area are unhighlighted and empty.

2. In Sisoft, it has a SiS 645 w/ PC2100U and a P4 with 256 L2 Cache (only difference is that I have a 645DX chipset). It gives a reference bandwidth of 1990 Mb/s. My stress test gives 1450 Mb/s.

Another funky thing I've seen is that in the BIOS it lists the Clock Frequency Multiplier as 10X, but on boot shows 17x100. I manually changed it to 17, but it still seems weird that if I reset all of the defaults it goes to 10x, but boots at 17x....

P-X

 

[LTC8K6]

Under the SPD tab I have different numbers for different speeds 133 and 166mhz. It is version 1.26 of CPU-Z. The memory tab lists the actual frequency the memory is set to and the FSB-DRAM ratio along with all of the timing settings. The timings under the SPD tab for 166mhz are also the same as the timings under the memory tab.

I would say your ram is definitely running at 133.

Sandra is not very good, so I wouldn't rely on it.

Intel chips ignore any multiplier settings other than the one Intel gave them, so it will always default to 17 anyway.

You might look for memory ratios in your BIOS, but I'd leave it alone.

 

[PrinceXizor]

Ok....here's the final scoop.

1. Setting the memory timings to very fast was what was causing the instability. I backed them off and no lock-ups any more.
2. I'm 99.9% sure the memory was running at 100Mhz not 133Mhz. See No. 3.
3. I finally found the Ram/FSB/PCI timings adjustment in the BIOS. It was called something different and set to "Auto" so it didn't jump out at me. I set the ratios to 100/133/33. I reran Sisoft Sandra and the bandwidth was 1900MB/s, right in line with what it was supposed to be according to the reference configuration that was closest to this computer. So, I'm making the assumption that the RAM was originally running at 100Mhz, not 133Mhz, since the throughput jumped so much.

Thanks to all who helped!

P-X