RAM isn't running at correct speeds

[CrazeD]

I currently have 2 x 512mb DDR400 Kingston, and 2 x 512mb DDR400 Crucial RAM running in dual-channel mode.

At stock CPU clocks, if I set my DRAM clock to DDR400, my computer won't POST. I can set it to DDR333 speeds, and overclock my CPU until it runs at 200MHz, but it won't run at DDR400 speeds alone. WTF?

 

[turtile]

Is it s754?

 

[CrazeD]

No, s939. Is it just because I have two different types of RAM that have different timings and such?

 

[reggie_da_man]

Is it s754?

Dual channel man. SKT 754 doesn't have dual-channel.

 

[NayNay1991x]

if you have 1 RAM which is faster than the slow ram it will run on the slow ram not the fast

 

[CrazeD]

Well all of it is PC3200, so I don't see why it wouldn't run at the correct speed.

 

[magouster]

I've read that when you use all 4 slots on some s939 mobos, the RAM reverts back to 166MHz, and won't run any faster while stable. Could it be that?

 

[CrazeD]

Hmm... you might have something here. When I get bored later, I'll take out two sticks and see what it does then.

 

[reggie_da_man]

I've read that when you use all 4 slots on some s939 mobos, the RAM reverts back to 166MHz, and won't run any faster while stable. Could it be that?

Yes that's %100 true. You can always overclock and get your ram back at 200MHz and gain a little bit of preformance at the same time from your CPU.

 

[magouster]

He could do that, yes, but in some cases, to get it stable at 200, he would have to run it with a 2T command rate, which severely cripples performance.