PAT suddenly causes serious instability

I installed the latest BIOS upgrade for my board (1015), and, despite my specific instructions to the contrary (by way of unchecking the checkbox for the same), ASUSUpdate cleared the CMOS checksum, and reset all of my BIOS settings. I shan't bore you with the details, but when I put everything back to where I thought that it was, it would reboot on entering Windows, as if it was overclocked too much. After much tinkering, I realised that the problem would occur whenever PAT was enabled, and would not occur when PAT was set to "auto" in the BIOS.

Although I cannot now remember for sure, I think that PAT was set to "enabled" before this latest BIOS upgrade. Even downgrading to 1014 did not help. I am somewhat confused as to why, even when I set my CPU to stock speeds, PAT should cause such severe instability. I thought that it might be SNDS, but since I can get it to overclock to just as fast as before without PAT on, and since PAT causes the failure even when significantly underclocked, I doubt that this is the case.

Does anybody have any ideas? They would be most welcome.

Specs below:

P4C [email protected] (250FSB, 1:1; 34C idle, 50C load; default voltage)
OCZ Gold dual channel, 2x 256MB (1.85v, active cooling)
Asus P4C800E-Deluxe
Windows XP Pro SP1

1.85v? vcore? if it is, isnt that too high? i mean, SNDS is for cpu with cvore 1.7v and above...

Err... I said 1.85VDIMM. Default VCore.

...Or maybe I meant 2.85?

2.85vdimm perhaps

Yes, that's right.

Hmm, I think that I've found what the problem is: the instability seems to be caused by setting "Performance Accelaration Mode" to "Enable" when "Turbo" is set to "Standard". When I set "Turbo" to "Auto" and "Performance Accelaration Mode" to "Enable", it worked.

I had no idea that the two settings were related. How very, very odd.

both my PAM and MAM are enabled as u can see in my rig below, although i have to raise my vcore and vdimm to get stability

jamespetts said:

Hmm, I think that I've found what the problem is: the instability seems to be caused by setting "Performance Accelaration Mode" to "Enable" when "Turbo" is set to "Standard". When I set "Turbo" to "Auto" and "Performance Accelaration Mode" to "Enable", it worked.

Click to expand...

I've seen similar stability problems on my board with PAM Enabled and Perf Mode Turbo / Standard. Memory benchmarks didn't show any improvement over just having PAM Enabled, so I only use the PAM setting and leave Perf Mode on Auto. I wish Asus didn't put PAT settings in 2 places. PAT is a chipset feature, so it makes sense to have it in the chipset menu. If Performance Mode settings affect something other than PAT, then Asus ought to clarify what the settings do.

krismcool, have u tried ctiaw? PAM increases ur mrb but only a bit.

Yes, I use ctiaw. The I875 and 865 chipsets handle PAT differently. There is no difference in mrb for a 875 chipset if any of the following settings are used:

PAM Enabled, Perf Mode Auto/Standard/Turbo, ctiaw shows PAT fully enabled & mrb reads the same
PAM Auto, Perf Mode Standard/Turbo, ctiaw shows PAT fully enabled & mrb reads the same
PAM Auto, Perf Mode Auto, ctiaw shows PAT reserved & mrb reads much lower

The fact that you got different results is likely due to your I865 chipset. And the 875 CS won't ever show PAT partially enabled - it's either ON or Off. That's why I'm questioning the multiple PAT settings. Others may have noted some difference, but I haven't with either a P4C800D or P4C800-ED. This goes for ctiaw, Memtest86, Aida32 and Sandra.

Possible solution

I have had the same problems. But as you can see in this test, the best result will accure when you set Performance Mode = Turbo and Memory Accelarate Mode = Auto.

My computer wouldnt boot up either with Performance=Turbo and Mem = Enable, and that was witg both 14 and 15'th BIOS.

This site/test will give a good view.

http://www.xbitlabs.com/articles/mainboards/display/asus-p4p800_8.html


But my own experience is that the best result wil accure with Mem: Enabled and Performance: Auto. Just like KrisMcool
Testet in SiSoftware Sandra's MEM-benchmark

ctiaw shows that my "system frequensy" is 533 and that my mem's are 266 and driving 1:1. Does if often fail ?
It does also say PAT = enabled

CPU-Z shows FSB 200, which will give the right MHZ too.

P4 2.6
P4P800 Deluxe
1024 DDR pc3200 Corsair
R9600 Pro

René

renet, look at my settings, im 24+ prime stable... today i ran prime again for 15 hours and no errors... both pam and mam are enabled

But what does that help if it isn't that setting that gives the highest performance!!??? With 2.85V can mine also boot up with both enbaled.

2.85v is good if you've got the kind of memory that won't fry in that voltage (like OCZ Gold, for example).

I havent fry'ed mine yet.
I have read about lot of people which runs with "mine" Corsair up to 3.1 V

But they get onlyl standard voltage now. I didnt get better performance by having both on enabled (Turbo and enable)

I only increase the voltage a little when i OC.

jamespetts said:

2.85v is good if you've got the kind of memory that won't fry in that voltage (like OCZ Gold, for example).

Click to expand...

or ram like mine

ciku said:

or ram like mine

Click to expand...

Why do you run 5:4, it sux. You should have bought at least pc3500, but its easy to be wise afterwards.

All hail 1:1

renet said:

Why do you run 5:4, it sux. You should have bought at least pc3500, but its easy to be wise afterwards.

Click to expand...

Well, my rig may suck but its stable, how bout urs? lets see ur rig... or maybe ur all talk talk talk? LOL wait till my new ram gets here

LOL mine's as stabile as yours! And 5:4 still sux !

But ofcourse it is, i hadnt seen that your CPU is the n00b-model. (533)