ram problem oc-ing

[woutertal]

ram problem oc-ing please help

I have a strange problem oc-ing my ram. I have an asus p4s800 with p4 2.8 @ 533 MHz. I have elixir pc3200 cl 2.5 ram, 768 MB of it.

Now just to avoid remarks on mobo and ram; I know the mobo is not the best for oc-ing, and that Elixir isn't the best around.

My ram works fine at stock speed with 2.5 3 3 7 (spd) settings

When I am overclcking the FSB from 133 to 153 => cpu @ 3217 MHz, I have to set the ram divider so it runs at 382 MHz (2x191), and timings down to 3 3 3 9.

Why is this? I would have thought that at this lower (382 MHz instead of 400) frequency, the ram would run fine at 2.5 3 3 7.

Can anybody ehd some light on this? I really miss something her that I need to understand to progress in the OC game (art?)

Also, please tell me if this post should be in another forum; perhaps the mobo one?

Your help is very much appreciated.

 

[woutertal]

Nobody ? I want to understand the numbers, please help.

 

[Sophisticated]

WELCOME TO THE FORUMS!!!!

what dividers are there?? how about you increase your Vdimm and see if you can run at stock timmings then

 

[woutertal]

Hi! thanks for answering. My board offers the following dividers:

at FSB 133-165 4:3, 8:5 and 4:2
at FSB 166-199 5:3 and 2:1

Vdimm is set to 2.7V, the highest available value in BIOS

I was hoping to reach FSB 166, cpu @ 3500, mainly because of the AGP/PCI frequency which at that FSB is back to stock (or should be). The memory should than, with the 5:3 divider, run at 400 MHz. I think that the cpu should be able to.. in fact the system boots fine, but hangs at a black screen (directly after detecting the ide bus) when booting to win (xp-pro) at FSB 166.

When I run the system at FSB 153 (the highest possible stable setting right now), I have to use the 8:5 divider, and I have to reduce the timings as described above. Why? The memory only runs at 382 MHz..

I am thinking of buying some better memory, pc3700 or pc4000. Will that sort the problem? or is this board screwing up when using this divider?

I cannot run the mem at 1:1, the option simply doesn't exist because of the cpu running at 533.

I am puzzled.

Thanks for your help.