P45 Chipset 8gb - Failing Memtest Test 5

[Cardnyl]

With 8gb plugged in I get intermittent errors on test 5 in memtest 2.10. The entire system is being kept bone stock. The stick timings and voltages are being manually set in the bios. Bios is version 1613. Other than pen and paper if there's an easy way to copy/paste my current bios settings let me know and I will provide them.

The Corsair kit occupies slots 1 and 3 (yellow and closest to the NB/CPU). I initially thought there might be something wrong with the patriot kit since the errors during test 5 were occurring in the 2-4gb and 6-8gb ranges. Testing of the kit by itself in both the yellow slots and black slots showed the kit to be quite stable. I have also tried swapping the stick positions (Patriot in yellow, Corsair in black) only to have the Corsair sticks, which have passed months of stability testing (48hr memtest, Lin Pack, and Prime95), fail.

I've read that 8gb puts some strain on the p45 chipset but always assumed that running 8gb at stock settings would be okay.

Additionally I have tried a NB voltage as high as 1.2v without any luck. Any tips you guys can give me to get these 4 sticks running stable at bone stock settings would be much appreciated.

[Mats]

What do you think about raising the Vram?

[Cardnyl]

What do you think about raising the Vram?

Could try it. During the troubleshooting process I tested each kit at both the recommended volts (2.10v) and much less than what they recommend (1.90v) without problems but the kits were tested in a 4gb configuration.

I have tried 8gb at 1.90 to 2.10 in .2v increments (lowest the board will allow) but results so far have been failures in test 5. I have also tried these volts with the nb set for its default of 1.10-1.20 with the same problem.

When I get home I will see if going beyond 2.1v helps getting past test5. I also have not tried loosening the timings but I would like to avoid that if possible since it should technically be possible to run 8gb at stock timings.

[tehfire]

Maybe try loosening timings to 5-5-5-15? I have 2x2GB and 2x1GB that each were stable at 4-4-4-12, but once I stuck them together I couldn't get it stable unless I switched the timings to 5-5-5-15.

[Nick Geraedts]

Mixing RAM often leads to problems like this. I'd suggest loosening the timings down to 5-5-5-15 and see if that aleviates the problem, and/or kicking the voltage up a notch. Both the Patriot and Corsair kits should be able to handle 1.9-2.0V without any troubles.

[Cardnyl]

Mixing RAM often leads to problems like this. I'd suggest loosening the timings down to 5-5-5-15 and see if that aleviates the problem, and/or kicking the voltage up a notch. Both the Patriot and Corsair kits should be able to handle 1.9-2.0V without any troubles.

When I was shopping for a second kit I made sure to pick out a kit that had the same rated timings and speed at a given voltage (in this case both Patriot and Corsair recommend 2.1v). Other than mobo factors (northbridge and memory tables in the bios) and memory factors (speed, timings and voltage) is there some other cause for kits of different makes/models not working well with each other (e.g IC incompatibility?). The reason I ask is because I should still be able to exchange the Patriot kit for a duplicate Corsair kit since the Patriot kit was purchased only a few days ago. If its something as simple as keeping all the sticks of the same manufacturer then I have no issues with a return. I just want to be sure this isn't some wacky quirk with the mobo.

The only timing that I cannot seem to adjust is the tRC value listed on the memory tab of CPU-Z. For those without access to a CPU-Z window this is the last value listed on the SPD tab below the Tras value (12). Not for lack of trying but there just doesn't appear to be a setting for it with a Asus P5Q Pro bios. CPU-Z lists a Trc of 21 for the Patriot sticks and 23 for the Corsair sticks.

I wish there was an easy way to dump the contents of the AI Tweaker section in my bios because I just feel as though I am not providing enough information.

I will definitely try out the 5-5-5-15 timings when I get home. Additionally I burned a copy of the latest memtest (2.11 currently using 2.10) just in case it was a software issue of some sort.

[ACook]

I imagine not liking the mixed kits is related to the same reason they sell kits rather than just let everyone pick single sticks for dual channel operation.

[Nick Geraedts]

When I was shopping for a second kit I made sure to pick out a kit that had the same rated timings and speed at a given voltage (in this case both Patriot and Corsair recommend 2.1v). Other than mobo factors (northbridge and memory tables in the bios) and memory factors (speed, timings and voltage) is there some other cause for kits of different makes/models not working well with each other (e.g IC incompatibility?). The reason I ask is because I should still be able to exchange the Patriot kit for a duplicate Corsair kit since the Patriot kit was purchased only a few days ago. If its something as simple as keeping all the sticks of the same manufacturer then I have no issues with a return. I just want to be sure this isn't some wacky quirk with the mobo.

Personally, I would save the time and just exchange the RAM. It's just "one of those things" that if you want maximum performance and compatibility, just use the same RAM throughout. When I upgraded both my server and workstation to 8GB, I went with two identical 4GB kits for exactly that reason.

That being said, in my short experience with my P5Q Pro, I found that it definitely didn't like 8GB at all. Shortly after that, the board decided to brick itself because of a memory issue when using 8GB.

[protellect]

try 5-5-5-15 @ 1.8v. I had memory failures with 8GB [i've assembled 6 machines with P35 Chipsets] running memory any higher than 1.8V, and timings any faster.

[Cardnyl]

Just to follow up

I burned a new copy of memtest 2.11
Retested the patriot kit under test 5 (about 100 runs) and tests 1-8 (20 runs) just to be sure. Kit did just fine undervolted and stock volted.

Tried both kits together at stock timings and volts with the nb from 1.2 to 1.28 and gave up when it was still throwing errors. Called the girlfriend at lunch to have her adjust the timings to 5-5-5-15 @ 1.9v, northbridge voltage at 1.10v (stock). Called her about an hour ago to find its still going strong with no errors. Guess its was the chipset holding me back; makes you wonder if this problem has been resolved with the i7's since the controller was moved off the mobo. I read around a bit and didn't see too much of a difference gaming wise between cas4 and 5 given equal fsb and cpu core speed.

[CA_Steve]

When you went from two sticks to four, you added significant capacitive load to the circuit. That added load at these high speeds slowed down the timing waveform of one or more lines enough to throw errors. Slowing down the timing allowed the race condition to disappear.

I doubt that changing memory brands will matter if they are spec'd for the same timing at the same voltage. Look at your mobo specification and see if it says the rated memory speed and timing vs using all four slots.

[Cardnyl]

When you went from two sticks to four, you added significant capacitive load to the circuit. That added load at these high speeds slowed down the timing waveform of one or more lines enough to throw errors. Slowing down the timing allowed the race condition to disappear.

I doubt that changing memory brands will matter if they are spec'd for the same timing at the same voltage. Look at your mobo specification and see if it says the rated memory speed and timing vs using all four slots.

I read through the manual but this specific bit of information didn't appear in it unfortunately.

I just wanted to thank everyone for all their tips and information; much appreciated.