P4P800 with DDR550 ram issues

[vader69]

I have Asus P4P800 with 3.20 Prescott. I got it stable at 245 FSB but my DDR400 was holding me back.

So I bought Corsair TWINX2048-4400PRO 2gig kit. After initial testing I could successfully boot to Windows 252 FSB - something I could never do before.

I started tweaking the latencies and running Prime for stability. Here is where things got weird. I could not get Prime to stay stable with the memory tests with even as low as 240FSB. However when I switched to 5:4 the stability improved. Ran Prime for 8 hours on 250FSB.

What gives here? Corsair sticks should handle 1:1 ratio at 255FSB. That's what I'd like to hit. Or at least 250.

Other stats. Vcore 1.6v, RAM 2.85V, water cooled CPU, GPU, NB. CPU >48C under heavy load, MB below 32C.

Did I just waist the money on the memory?

 

[WolfDragon]

i had that same issue with my p4p800, it would just go squirrely for no reason, which is why i am not running it anymore

i worked around it a bit by disabling most of the onboard devices thru the BIOS but i still could never clear 3.5 ghz nicely

i spent some time checking power around the northbridge and saw rather significant voltage fluctuations on my o-scope (no i dont rem the variance as i cant remember what i had the volts/div knob set at)

i imagine if you can find a volt mod for the northbridge and try upping the vmem a bit you'll get farther along than i did

if you havent already, i strongly suggest do the vdroop mod, it stabilized mine enough to let me stay stable at 3.4, before it i could only do 3.18

 

[vader69]

Should the droopmod be 33k or 28k resistors?

Some people stick in pods - can't really see point in that.

Any suggestions?

 

[1Tanker]

Should the droopmod be 33k or 28k resistors?

Some people stick in pods - can't really see point in that.

Any suggestions?

26 k IIRC

 

[1Tanker]

I have the P4P800 E Deluxe, 2.4C. I can only get the CPU to 243FSB. When

i use the 5:4 divider i could get:

OCZ3700EB-2x256-281MHz stable@3.3-3.4v(DDR Booster)

OCZ 3200 Platinum Rev2-2x512- stable@303MHz@2.85v

It might be worth a try to LOWER your RAM voltage to 2.75. Might be getting

hot. Just a thought, worth a try?

 

[vader69]

I backed FSB way off to 235, lowered vcore to 1.55v, and vdimm to 2.75v.

Ran Prime all night - stable as can be.

I am not really getting my money's worth out of my DDR550.

P4P800 also has an issue with PAT (MAM) if fsb is over 200.

Has anyone here flashed the bios with P4P8X to get a 533MHz strap?

I read somewhere that while temporarily flashing to P4P8X it may destroy the raid array. What about if I disconnect the drives while flashing.

Is nabling PAT over 200FSB worth the hassle.

The only reason I haven't tried this is the fear of losing the RAID array. Too much data to restore.

 

[1Tanker]

I've never had problems with MAM, I use it, and Turbo@243 on my P4P.

Same with PAT on my P4C800. :?

 

[Scougs]

I went to Corsair's website and looked up your memory. The pdf for you memory says that it was tested on an AMD dual channel motherboard at 275MHz (DDR550). It is possible that it just won't be stable at that high of speed on an Intel platform. You could try increasing the memory voltage as well. I don't know anything about the vdroop thing but I have heard other people talk about it so you probably want to look into it.

 

[vader69]

I've never had problems with MAM, I use it, and Turbo@243 on my P4P.

Same with PAT on my P4C800. :?

I thought that PAT is not working over 200FSB on those boards whether you enable it in bios or not. That's why there is a bios flash that installs P4P8X bootsector that enables 533MHz strap. After that you're stuck with 1:1 ratio but it works when using higher frequency ram.

I will try this flash and post the results.