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Tough RAM OC'ing! WHY?

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Mike360000

Member
Joined
Mar 28, 2001
Location
Stokesdale, North Carolina
Hi All,
I have a problem concerning oc’ing my ram that I can’t figure out at all!
I’ve done a fair amount of oc’ing, but I’ve never came across a problem
like this.

I have a P4 1.7 ghz on a Abit BD7 Raid mobo. I also had the same P4 on
a BL7 Raid before the BD7 Raid I have now. So the problem also ties in
to that mobo.

With the BL7 I used 712 meg (3x256 sticks) of Corsair SDRAM PC133
CAS2 ram. I could overclock this ram to 127 fsb, giving my cpu 2159 mhz.
BUT I could never start the ram from 3:4 BIOS setting, which would have made
the fsb 133 to start with. To get the 127 fsb, I had to start my ram at a 1:1 setting,
starting my fsb at 100 mhz. When I had to run the ram at 133 fsb, it limited
my overall oc to about 118 fbs on top of the 133, giving me a total oc of
about 151 fsb. I ran this setting because the memory bandwith was greatly
increased to about 1200 in 2002 Sandra benchmarks. CAS settings at 151 fsb
was 3-3-3, without precharging. I could run these settings at 2-2-2 with precharging, starting at 100 fsb.

About a month ago I went to a Abit BD7 Raid DDR mobo, of which I had hoped I
could increase my fbs, getting both higher cpu oc’ing as well as higher bandwith.
But it was not to be the case. First I used some Crucial 2100 DDR ram I had. I
Had run this ram before at 159 with no problems. However once again, with
This Crucial ram I was limited to practically the exact same oc’ing numbers/mhz
as I was with the Corsair SDRAM. With a 100/200 fsb I could oc the ram about
27/127 mhz, or about 154/254 mhz. Or if I started at 133/266, I could oc my ram about
18 mhz ontop of the 133/266 settings for DDR. I kept my BIOS CAS settings the same for all ram oc’ing here, at 2.5-7-3-3.

This past week I got some *supposedly* real good oc’ing ram. I got 2x256 sticks of
PC3000 OCZ with copper heatsinks. This ram *supposed* to oc to 200 mhz! To make
a long story short, I am still stuck with the same oc’ing numbers as I was with my Corsair and Crucial ram. Matter of fact this OCZ ram may bit a bit more finicky. I can ONLY run this ram with the following BIOS settings. 2.5-6-3-3. Anything else, regardless to oc’ing or not will not run With this ram. I can start my fsb at 100 and oc my cpu to about 127. or
I can start my fsb at 133, and oc my cpu about 18 mhz on top of the 133, giving me a
Total fsb of, again, 151 mhz…..

My big question or problem here is; I know my cpu will oc to 2159 with no problems,
but it will only do it if I start I start from a 100 fsb. My ram *supposed* to go much higher than this, but it won’t if I start at 133 fsb! I have also tried turning my ram voltage
up, but that has only helped marginally, if at all. I have also tried the *FIXED PCI* settings, and I still can’t get any better results! So what is the problem with my ram and setup here? I am at a loss!

Thanks for reading such a long post!
Mike
 
Well a pci card would be the first thing that would come to mind, except with these Intel/Abit mobos, there is a *fixed* pci/agp divisor setting, that locks the pci and agp to 33 and 66. Of course I have the option not to use it, but my results are same regardless.

Thanks,
Mike
PS Any other ideas?
 
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