My experience with RAM combinations and a picky board

[BlueWeasel]

I've got a 8RDA3I board (Nforce2) running a combination of Mushkin PC2700 and generic PC3200 RAM @ 200 FSB. The problem is the generic PC3200 sticks only run stable at CAS 3.0, and the PC2700 doesn't like to be set at CAS 3.0.

Using the CAS 2.5 value in the BIOS, Windows loads fine, but I get errors in both Prime95 and MemTest.
Using CAS 3.0 with the Muskin RAM results in the system freezing at the BIOS screen.

Is there anyway to change the CAS value to 3.0 once Windows loads?

[Update @ 11:30]
Apparently, it's a picky board that's causing my problems.

I took each RAM stick and ran it in slot 1 (channel 0). All 3 RAM sticks passed Memtest's test #5 at 210 FSB with about 2.75v running on CAS 2.5 (even the PC2700). If I take the 2 sticks of generic PC3200 and put them in memory slots 1 and 2/3, then I get errors in Memtest on tests #5 and #8.

So now, I've put the PC2700 in slot 1, and the 2 sticks of PC3200 in slots 2 and 3. I'm still running in dual channel mode and I'm running a full Memtest pass to see if I get errors. I'm kinda amazed that the PC2700 appears to be running fine at 210 FSB even though it's Mushkin basic green.

 

[xtknight]

Well if it freezes at the BIOS screen then it's a bad setting. In short, you can't, no. Sorry That just happened to me today, when I increased the CAS by .5. Not sure why INCREASING it would result in instability, who knows, maybe it just has to be what it's meant to be at.

 

[Gamingphreek]

Yes but it requires a restart. Just leave it at Default settings. It makes very little difference.

-Kevin

 

[InlineFive]

There is no way, not to mention that if some of your memory is running unstably over spec you might end up with a corrupted HDD. I would ditch the PC2700 memory.

 

[BlueWeasel]

Ahh, that's what I was afraid of.

It's a shame that I've got a stick of PC2700 that runs fine at 200 FSB on CAS 2.5, yet I can't get a generic stick of PC3200 to run at CAS 3.0 even with 2.9v. Oh well, that's what I get for getting generic.

 

[TheStu]

well heck in that case drop the PC3200 if the PC2700 is such a performer.... or run one stick at a time and memtest them... or Sandra to see which stick offers the best bandwidth.

 

[BlueWeasel]

Well, I ran memtest overnight on the PC2700 (9 hours @ 2.5-4-4-11) @ 200 FSB with no errors. If I try to run the PC3200 at 2.5 CAS, I get errors in Memtest at the end of tests #5 and #8.

I was thinking about picking up a stick of 512mb Muskin PC3200 from Newegg to replace the PC2700, but I wonder if I'll have problems trying to run the new PC3200 at CAS 3.0.

It's just odd that the Muskin RAM does like the slower CAS setting. I don't have a problem running at CAS 3.0, but I just want to make sure that the new Muskin PC3200 shouldn't have any problems running at CAS 3.0 with the other 2 sticks of PC3200.

 

[xtknight]

Huh?? I'm confused.. When you get the new stick just run at SPD settings. Anything wrong with that? Or you want to overclock it?

 

[BlueWeasel]

Actually, after more benchmarking, it appears that it's a picky board that isn't as stable in dual channel mode compared to single channel (well, doh, that's a known).

I've edited my original post to reflect my findings.