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PC4400C25PT and Intel at 275mhz


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Hello all,

 

I just picked up 2x512 cmx4000c25pt & seem to be having a problem with them. Set them up to run at 275mhz, 2.5-4-4-8, 2.70v / reading 2.75v in Abit EQ. CPU is at 275mhz multi dropped x14, 1.48 vcore / reading 1.44v.

 

First run out was a 10 hour memtest86+ v1.55. Came up with no errors. Then tried to run prime95, which failed with a rounding error within 2 minutes. Also tried Super PI 32M calculation, which also failed within 2 minutes. I tried loosening the timings to 3-4-4-8 also tried upping the vdimm to 2.80v bios/2.85v A EQ. Both prime95 and Super PI continued to fail.

 

Set vdimm back to 2.70v, timings to 2-3-3-5, and a 5:4 divider. Super PI can complete the 32M calculation now and prime95 torture has been running a few hours now. That should show the cpu is not the problem.

 

Any suggestions as to what I am missing to run 1:1 at 275mhz?

Sys spec in sig.

 

Thx

JLK

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You are safe up to 2.9v and within warranty. You could try that. Also, what MOBO and do you have any of the turbos or other perfomance modes turned on?

 

Mike.

 

Hey Mike,

 

Thanks for the reply. I'll try 2.9v tonight.

 

I have an Abit AI7 mobo. I have my GAT (what Abit calls PAT on a i865) set to A-A-A-D-D. CPUZ and Everest Home show PAT is disabled, which it should be when set to A.

 

BTW, PAT won't enable either - I just discovered yesterday. I tried to force it while running the 5:4 divider by changing the first A in the list to Turbo and/or Street Racer. I even tried setting the FSB back to 200 and the RAM to SPD. Still won't turn on performance mode.

 

The odd thing to me is memtest shows NO errors, but it won't work correctly in Windows. I plan on moving this CPU & RAM to an Abit IC7-G Max2 in the near future. I'm wondering how it will work on the 875 board.

 

Thanks,

JLK

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PAT is a feature of the Intel 875P chipset and is not available on the 865 based MOBOs. GAT is totally different from PAT and is a performance mode, like turbo. These modes can interfere with your manually set timings and OC settings are IMO are better left disabled.

 

And, I am running a socket 478 prescHott in an ASUS P4C800E-D and I also ran it in an ABIT IC-7 MAX3. Both cases were using the PC440C2.5. It runs great with the prescHott on the 875 MOBOs.

 

Mike.

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Hey Mike,

 

I bumped the vdimm to 2.9v. I ran memtest86+ v1.55 and got errors in test 5. Took one stick out & ran memtest, no errors. Switched sticks and got no errors. Put both in, but in slots 2 & 4 instead of 1 & 3, got no errors.

 

I completed a super pi 32m run, which had not worked before. Need to run some longer tests, but things seem to be looking up.

 

Thanks again

JLK

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Don't forget you have to consider the phase of the moon too! :D:

 

Hopefully I will have the time to swap mobo's this weekend. We'll see how it goes.

 

EDIT: Well I swapped the AI7 out for the IC7-G MaxII. I set the fsb to 275, the multi to x14, and vdimm to 2.8v (mobo max). Memtest won't even start. :eek: I'm going to give up on the x14 multi and look for some nice PC3200 2-2-2-5.

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