4 Sticks of ram?

[Genome852]

I have 2 pairs of ram sticks, one pair is CAS 2 DDR400 and one is CAS 2.5 DDR400.

When I use them all at once, I have to set the memory frequency to 100mhz (so it's ddr200) otherwise I get an error saying "cpu is now in safe mode, please resetting cpu frequency in bios or press f1 to continue." I also remembered to set the thing to 2t when using all 4 at once, but it doesn't help.

Anyone know why?

Specs

Athlon64 3500+
7900GT
Chaintech VNF4 Ultra
4x512 ddr400

Oh and is it even worth it to put the 2 extra slower sticks in? When I do, my tras speed or whatever goes to 15T instead of the 8T with the faster pair, and I get to use 1T setting if I just use 2 sticks instead of four.

 

[Rik]

You should never ever mix different speeds of ram.

 

[Mictlantecuhtli]

Can't you set memory speeds manually?

Some memory modules (or brands) are very sensitive to some speed settings. For example, I have one Transcend DDR400 512MB module (CAS2.5) that doesn't work with my mainboard if I set RAS-to-CAS delay to 3 or more.

 

[Genome852]

Here's the stats for the ram sticks

2 sticks:
Size: 1024mb
Frequency: 201.0 MHz
CAS Latency: 2 clocks
RAS to CAS: 2 clocks
RAS Precharge: 2 clocks
Tras: 5 clocks
Trc: 12 clocks
Command rate: 1T

Or (all 4 combined)
Size: 2048mb
Frequency: 201.0MHz
CAS Latency: 2.5 clocks
RAS to CAS: 3 clocks
RAS Precharge: 3 clocks
Tras: 8 clocks
Trc: 12 clocks
Command rate: 2T

Which would give better performance?

As for the "safe mode- press f1 to continue" thing, I know it doesn't have to do Ras to cas delay etc. because wouldn't that mean that even after I set the memory frequency lower, the computer would still show the message on bootup? That isn't the case :/

Could it have to do with the single-sided / double-sided ram combination? (even though it worked on my old K8N Platinum motherboard) Or maybe my motherboard just sucks? O_o

Thanks in advance

 

[Mictlantecuhtli]

It could very well be an issue with single- / double-sided modules and the compatibility with your mainboard.

Maybe there's a BIOS update that could help?

 

[Genome852]

Yeah I thought about that, but I don't have a floppy disc drive and I don't know how to flash the bios either way. Thanks for the help though.

So the problem is the motherboard then, cause my old one had no problems with these 4 sticks. Ah well, that's what I get for buying budget motherboards >_> Using all 4 sticks at once with ddr400 wouldn't cause anything to fry right? So everything's good except for that annoying message right?

Oh wait hold on, which set of would give better performance? Cause if having just the one pair in use would give better performance, I could give the other two to a friend.

 

[Goalie]

Generally a lower CAS will give better performance all other things being equal. Since both sets are DDR400, you'll PROBABLY see best performance with the CAS2 RAM. That being said, there are plenty of other factors that can invalidate this. Best bet is to find some benchmarking software and run each set of RAM against it. Truth be told, if the sets are similar other than the CAS, you probably won't physically notice too much of a difference.

If your old motherboard had no problem with all 4 sticks, yes, I'd say the problem is either with the new motherboard, or finding that exact set of timing settings that will work with both sticks as Mict. said.

Personally, though, I follow Rik's advice- the world is generally a happier place if you don't try to mix.