Overclocking E6420

[Shinare]

Well, I just got a new C2D system, an E6420, gigabyte P35-DS3R, A-Data DDR2-800, 8800GTX, Vista x64, 550W Dual Rail ActivePFC PSU, 2x 320GB HDD and a DVD burner.

I am able to run the fsb at 375 at which point the cpu is at 3GHz even. The memory is, unfortunately, at 940 something or around there sso I let the BIOS loosen up the timings. and added +.2v. Anyway, two instances of Prim95 passed OK, ran memtest #5 for an hour with no failure. 3DMark06 Benched with 11100 3dmarks just fine.

I try to play Need for Speed most wanted and the game locks up about 5 minutes into playing it. Every time. I even tried BF2 and it CTD'd after about 20 minutes with a "BF2 Memory Error".

I increased mem voltage, NB voltage, PCIe voltage. No help.

I lowered the bus to get the memory running stock 800MHz at the lowest divider. At that point I believe the processor is running at 2.6GHz or something like that. Games still behave the same way.

I lowered everything back to stock. Games play just fine.

What could be causing my games to crash when memtest and Prim95 both complete with no errors?

 

[adairusmc]

Is spread spectrum disabled?

PCI clock sync fixed at 33Mhz?

PCI-Express clock fixed at 100Mhz?

I am not as experienced at overclocking as some people here, but having those settings has caused instability for me in the past.

 

[SerpentRoyal]

Use 1:1 memory divider for RAM speed of 375MHz. You did not adequately test RAM and CPU.

 

[Shinare]

PCIe freq was set at 100MHz. Can you be a little more specific on how I didnt test it adequately? I primed out just fine and ran memtest86 for over and hour.

The settings for the memory divider are a little odd in the BIOS. I set it to its lowest setting in the list which caused the RAM to be a little faster than designed. I'll take anotehr look at it tonight and see if there are other settings in the list that actually make it run at 1:1.

Thanks for the help.

 

[Shinare]

Set the fsb to 375 and mem ratio 1:1 (375MHz). PCIe 100MHz. All stock voltage. Memtest86+ #5 five times no errors. Full Memtest86+ two hours, no errors. SP2004 Orthos Blend Passed no errors. 3DMark06 finished and posted 11.1K again. Fired up NFS:MW and played for about 15 minutes, hard lock. Had to push the reset button.

I'm boggled. NFS:MW works fine at stock. I cant believe that this chip will do 3GHz on stock voltage, retail fansink and perform flawlessly until I get into a 3D game. You suppose my 550W just aint enough to cut it? I dunno, how much more current does it take to OC when your not over-volting anything?

 

[SerpentRoyal]

Need to run Memtest of Orthos for one day each for this problem. The fact that it works at default setting tells me that your overclock is no good. I would wager that the rig is stable at 250 to 300MHz FSB with 1:1 memory divider (same as FSB speed).

 

[Ika]

Lower your OC and see if NFS:MW still locks up. If it doesn't, there's your problem.

 

[Trevante]

Stock heatsink? What are you temps like? They're probably really high which may be part of your problem. Go get a better CPU cooler or lower your overclock.

 

[Finnkc]

Yea drop the OC down and see ... then ramp it up slowly ...

 

[Noubourne]

The 8800GTX pukes out heat like a dragon when you're stressing it. Try using ATItool or some other graphics stress program while running Prime95 and see if it locks up.

Also, proper Orthos/Prime95 runs are at LEAST 12 hours, not 1 hour. I had several OC failures at 2.9Ghz on my Opty at 7-10 hours in. If I followed your methods, I'd still be at 2.9Ghz - and crashing all the time like you are.

One guess I have is that you are pushing your case ventilation to the limit when gaming due to the heat output of your GTX, which can cause your CPU to get too hot to run. This is causing the lockups.

Also, if you have poor ventilation on the GTX, you could very well just be locking that up.

 

[Shinare]

Looks like it was the 2GB barrier thing that was posted on the front page a while back. I did the /LARGEADDRESSAWARE flag hack on the two games that were causing problems and that fixed the problem. I'm not sure why that didn't cause a problem at stock speed. However, with that flag in place, and I'm running Vista x64, it hasn't locked up at 3GHz.