RAM speed limit

MichaelHo · 14 Jul 2007 at 15:28

I have 2 gig DDR ram (g skill zx) running on my DFI nf4 ultra-d motherboard. I am trying to overclock my cpu and tried to put a divider on the RAM speed to 200.
However I put the CPU bus speed up to 210 (original 200) and the memory is now also clocked up to 210. Shouldn't this stay at 200 due to the limiter?

Cheetah Designs · 14 Jul 2007 at 16:18

No thats just the speed at default settings, you have to look at the ratios. Setting the RAM at 200 FSB will be in the ratio of 1:1 which is not what you want.

ChrisD. · 14 Jul 2007 at 17:41

You need to set it lower then 200 mate, try 186 or 166 (I think they are the numbers). When you push your FSB up your CPU will over clock but your RAM will stay close to 200 effective due to the divider and higher FSB.

MichaelHo · 14 Jul 2007 at 18:45

I have just tried to use 166 and 186, but it doesn't seem stable at these speeds, windows boots but then the pc restarts.
If ratio I see is 05/06 is this the correct formular to use:

05/06 = effective mem speed / FSB

therefore for FSB of 220 at 186 ratio I would get

09/10 = effective mem speed / 220

effective mem speed = 198

is this right?

ChrisD. · 14 Jul 2007 at 20:04

MichaelHo said:
I have just tried to use 166 and 186, but it doesn't seem stable at these speeds, windows boots but then the pc restarts.
If ratio I see is 05/06 is this the correct formular to use:

05/06 = effective mem speed / FSB

therefore for FSB of 220 at 186 ratio I would get

09/10 = effective mem speed / 220

effective mem speed = 198

is this right?

Yes that's right. So it's your CPU causing the restarts, as the RAM at that speed is stock. Depending on what you have, most DDR RAM is more then capable of handling a 20 MHz jump.

What is your VCore? Perhaps your CPU needs a little more juice to get the stable overclock?

MichaelHo · 14 Jul 2007 at 21:59

its managed to do 220 recently. I had a pair of unmatched 512MB corsair value ram in and set that to 166 and clocked the cpu up to 220.
So I doubt it would be the cpu?

I have the G skill ZX 2 gig kit, suppose to be a pretty good clocker.

ChrisD. · 15 Jul 2007 at 00:04

What are the RAM timings? And what VCore have you got running? I don't the the RAM is at fault here mate.

MichaelHo · 15 Jul 2007 at 09:38

vcore is 1.36V and ram timings are 2-3-2-5 1T

Why do you think that the cpu would go to 220 with the unmatched pair of 512mb but not with the matched pair of 1gig sticks?

ChrisD. · 15 Jul 2007 at 12:05

What CPU is it you've got? You could add another 100mV and see if that works. Not sure about the not booting with the good RAM thing though, did you try running them in the other channel?

MichaelHo · 16 Jul 2007 at 08:40

its a amd64 3500+ venice core.
In bios is it the CPU VID voltage i have to increase?

FreeStream · 16 Jul 2007 at 09:21

MichaelHo said:
DFI nf4 ultra-d motherboard.?

Says it all TBH. My SLI-DR never played ball with dividers.

Biggest pile of utter tat i've ever had :rolleyes:

MichaelHo · 16 Jul 2007 at 10:04

but everyone keeps telling me that this motherboard is like the best ever for overclocking.

FreeStream · 16 Jul 2007 at 18:52

MichaelHo said:
but everyone keeps telling me that this motherboard is like the best ever for overclocking.

Maybe it is, but the two I had were ****.

I've still got one, its at 220x10, 1:1, 1.4V with latest BIOS and a X2 3800+

Won't do over that without crashing at least once a day.

NF2 NF7-S and this P965 P5B-D are/were SOLID!!!