Problem with a friend's client's I7 machine

So I'm helping out another business owner. He built this gaming machine for a client and it's randomly rebooting:
-eVGA x58 micro
-i7 920 stock cooler
-Antec 650w earthwatts (also tried another PSU)
-Vista (have to check which version)
-3x2gb Patriot DDR3-1600 9-9-9-24 1.65v (also tried a corsair 1600 set, identical specs)
-evga 9800gtx

I came to his office and I see a GTX260, a 9800gtx, a Seventeam 850W PSU that he also swapped with and tried.

So I come in here an tried the machine with the corsair ram and loaded optimized defaults, which set ram to 1066.

I ran small FFT and it was going fine for at least I'd say 30min, checked up on it every 10min, and the last time I came back it was in windows desktop with nothing running (obviously rebooted).

I downloaded evga's leet OCing software and all 4 cores were in the high 70s. Also, I placed a nice big blizzard fan blasting over the whole system, b/c originally the NB and SB chipset heatsinks were SCORCHING HOT to the touch... but once I placed this fan over the system, they seemed fine.

I checked the PSU with a DMM and it's well within spec.

I'm still working on this, but any quick pointers out there? I've NEVER touched an i7 system before...

Could be a memory problem. Try upping the QPI voltage, which controls the voltage for the memory controller on the i7 cpu. My system was exhibiting the same symptoms, random reboots while priming (using blend though). This was using stock memory clocks and timings.

Intel spec allows up to 1.35v for QPI, so I would try setting it to 1.35v and see if it has any effect. Also play with the command rate setting. Try 1T and 2T and see if that has any effect. Originally I had a problem with a 2T command rate, and switching to 1T actually improved stability.

Also make sure the uncore multiplier is twice that of the dram divider. So if you have your memory divider at 6, uncore would be set to 12.

downer said:

Could be a memory problem. Try upping the QPI voltage, which controls the voltage for the memory controller on the i7 cpu. My system was exhibiting the same symptoms, random reboots while priming (using blend though). This was using stock memory clocks and timings.

Intel spec allows up to 1.35v for QPI, so I would try setting it to 1.35v and see if it has any effect. Also play with the command rate setting. Try 1T and 2T and see if that has any effect. Originally I had a problem with a 2T command rate, and switching to 1T actually improved stability.

Also make sure the uncore multiplier is twice that of the dram divider. So if you have your memory divider at 6, uncore would be set to 12.

Click to expand...

What's uncore?
Also, no idea what QPI is but I guess I'll test that.

By the way, the system doesn't only reboot from prime95... it will also randomly reboot from the OS while sitting idle.

On top of that, my friend said it's even booted from BIOS.

I'm still learning my way around the i7 platform. I've only had my current setup for a couple weeks now.

Uncore is basically the frequency the Integrated Memory Controller is operating at.

I think QPI is kinda like AMD's HTT, connecting the CPU with the chipset.

Have you tried posting at EVGA's forum? That might prove more helpful.

I don't have time to post there right now... maybe tonight I will, but I'm only trying to help and I had to travel 25 miles and over a bridge to get here.

Now, why the heck is the i7 920's multi showing up as 21x!!? Isn't it supposed to be 133x20? It's running 2.8ghz with 133x21...
Well that's for core0, the others might be at 20x, but I've no idea how to know for sure.

21x is when the processor is running in turbo mode. When only one or two cores are in use the cpu multiplier is increased to 21x, for a performance increase. You might try disabling that feature as well. It might be called Turbo boost or Turbo mode in the bios. If there is no direct Turbo feature listed that can be enabled or disabled, you can disable EIST = Enhanced Intel SpeedStep, and that will disable turbo mode.

Doesn't seem likely that it is causing your problems, but it's something else to try.

Alright, so my friend left me @ his office and told me to lock up when I was done.

I wanted to narrow down things as much as possible, so here's what I did:

• Took the entire machine out of the case.
• Placed motherboard on top of motherboard retail box
• Pulled off the stock heatsink and cleaned with my ArctiClean solution
• Reapplied new thermal paste (Shin Etsu) and reseated the stock cooler (had some trouble with one of the 4 posts and I'm wondering if they didn't have it seated properly the first time (but temps were within spec, so who knows)
• Only plugged in the OS drive (raptor 150gb) with a different SATA cable than before
• Plugged in ONE stick of 2GB Corsair 1600 in slot 1
• Plugged in the eVGA 9800GTX
• Plugged in the Seventeam power supply (850W)
• Used onboard power switch
• One USB port hooked up to wireless receiver for mouse/keyboard
• DVI to LCD
• ethernet cable

So that's it... just what's necessary... HDD, video, RAM, CPU, board, PSU. Everything else is unplugged and the parts are out of the case. Turned on the system and tested PSU with DMM. All 3 rails are within spec. I think it was something like 12.24v, 5.16v, 3.3X (don't remember that one)... and when I ran prime, the 12v didn't really budge.

I cranked a the blizzard fan to max setting and it's blasting over the entire system now.

Everything loaded defaults in BIOS and set vdimm manually to 1.65v. Speed step and C*E disabled.

Everything else left auto, including RAM timings.

So far it's been blend priming for 2.5 hours, probably longer than it's ever been able to stay on. My friend is quite happy, but I hope he knows what to do from here. We're going to catch up over the phone again (just got off phone w/him now and he's happy).

I'm going to have him snap things back into it one-by-one. I still don't know if it was a heat issue, hardware issue, or power issue.

*Side note*
I think I'd heard about it but totally forgot that the I7 does hyperthreading and comes up with 8 cores in task manager... is it really that beneficial to have 2 virtual cores per physical core (assuming I worded that correctly)?

Still playing with my new one myself so if the multiplier is at 21 with turbo on it's only running a couple cores ?

I'd been priming things on 8 cores pretty stable and havent messed with it a lot yet, but it primes ok so far with 8 HT running with turbo on.

Glad to hear it's working for you thus far. Wonder what it was exactly? i7 is so much more confusing than 775 was.

I think hyperthreading is beneficial for certain applications, like encoding. For gaming, hyperthreading can actually decrease performance. I turn HT off since I primarily use my computer for gaming. Decreases load temps by about 10C with it disabled.

MongGrel said:

Still playing with my new one myself so if the multiplier is at 21 with turbo on it's only running a couple cores ?

I'd been priming things on 8 cores pretty stable and havent messed with it a lot yet, but it primes ok so far with 8 HT running with turbo on.

Click to expand...

From what I read turbo is only for one or two cores.

http://www.tomshardware.com/news/Turbo-Mode-Intel,6193.html