Need some overclocking help

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just1tree

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Apr 4, 2007
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I got tired of oblivion beating my system down so i felt it was time to upgrade, but wanted to do it a little at a time. So i got a A8N32-SLi for the socket 939 platform, with an 8800 gts. Here is my current system components:

A8N32 Sli Deluxe
AMD 4000+ San Diego
EVGA 8800 GTS 320 Superclocked
Scythe Ninja Ultra revision 2 Heatpipe tower
2x512 Kingmax DDR500
HIPER Type R 580W PSU
2x80gig WD raid 0 SATA

So i get the system put together and up and running. Run some stress tests with like oblivion, prime95 etc and things look cool. Temps are good on the cpu, system temps were hot but i found that when i put the fan on the mobo heatpipe that they came down. So i decided to try my hand at oc this bad boy. I was able to get this same cpu to 2.8 on an MSI K8N Neo 2 so i figured that would be my goal here as well. I kinda followed the Anandtech forums quick and dirty isolate/combine process for overclocking and found that my cpu would run prime 95 without errors to 2820 mhz. The mobo would take it's FSB over 330 with the cpu multiplier down to 7, and the memory tested good with memtest to 255.

However, when i went to put a combo of fsb 250 x 11 for a 2750 speed 3dmark 2006 would bomb out on the first test with graphical errors. The computer itself wouldn't crash though. I could escape out of 3dmark and it would just tell me the test was aborted. I tried firing up oblivion, and the same thing happened, tons of grapical errors but not system crashing and returned to desktop ok. Prime 95 ran without errors as well. I kept trying to play with slightly lower values and found that the only speed i could run was 11x235 for a 185 mhz overclock =/

If prime95 doesn't run into any errors, but 3dmark and oblivion crash out what could it be? I was thinking i could try to slow down the memory in case that was the problem, but I don't see how that could be if i could run ok at 10x250 without a problem. I'm certainly dissapointed that i can't get more out of this overclock at the moment to not bottlneck my video card so much. Any ideas or suggestions would be appreciated.

*NB HTT ratio is 4x
*SB HTT ratio is locked at 5x by 200 frequency

i've also tried increasing cpu voltage, but it makes no difference.

thanks for the help.
 
I'm ASSUMING you've locked the PCI and PCIe busses... Correct?

Try 230x11 and see if you get the same instability.

What's your CPU Vcore? RAM voltage?
 
Yes, the pci-express bus is locked at 100. Ram Voltage is currently set to 2.6v, but while attempting to overclock i had set it to 2.8v. But it didn't seem to make much difference.

Now CPU voltage on this board is unlike any other i have used. If i set the overvoltage 200mv to disabled, and attempt to set my voltage i.e. 1.5v, it will set at 1.45 volt. No matter what voltage i specify it always reads 1.45 v in the bios and in speed fan etc. Now if i turn overvoltage on, and i change the voltage i.e. 1.15 the voltage now becomes 1.35 etc. I will try to increase the multiplier and drop the fsb to see if that helps the instability. I think i might have tried that but now that you ask i can't remember for sure.
 
i'm at work right now, but i know that I let it default to SPD which i think is CAS-3.0, 8-4-4.
 
How long did you ran Prime95 for? Also, have you overlcocked your video card?
 
ran prime 95 for a good 20 minutes at 2820 mhz and it had no errors. And the video card comes factory overclocked to 570 vs 500 stock i think it is. But i haven't overclocked it further. Figured I'd start with the cpu first.
 
you need to run prime95 for at least 8 hrs for fully stablility of the CPU.
 
Why don't you try underclocking your GPU for a little bit... Just to see.

Maybe 480 on the GPU and -150mhz on the RAM?

How high can you get it that it won't crash in 3D? 2400mhz? 2500mhz?
 
I took Arcygenical's advice and took the memory out of the equation by lowering the fsb and increasing the multiplier to 12. So I set my FSB to 235 x 12 for a 2820 and directly ran a 3dmark 2006 test. The whole thing ran fine, so i started up prime 95. I noticed that when my cpu temps went from 44 idle to 52 prime 95 ran ok, but when it hit 53 it had an error. I went back and set the fsb to 233 and reran 3dmark (which ran ok). Prime 95 this time had no errors as well.

I should also note that i have my ram voltage set to 2.75, cpu core at 1.45 -(asus probe reports 1.49 hmmm... ). I'm partly wondering if my case and it's cooling efficiency or lack thereof is the problem. I have a steel Chenming tower case which has 2 80's pulling in the front, 1 80 in the back, and i had to put a 120 in the side window to pull in cool air over my video card. Yesterday i added a 120 into the 5.25 bays with some zip ties to pull in some more cool air over the Ninja tower which seemed to help. I'm going to run prime 95 all day while i'm at work to see if it's stable.
 
Hmmmm...

Why don't you drop your RAM speed even further through a divider and see if you can increase the FSB a bit higher...

As long as you're over DDR300 (150mhz) you won't suffer any performance hits.
 
definety temp prob. 2 ways to solve it. lower ur FSB or get better cooling. or get a better circulation inside ur computer.
 
I bought the Scythe ninja based off anandtech's review along with the silenx extreme 72cfm 120 fan. But i think you are right, i think it's a circulation problem. But dropping the memory speed a little bit and increasing the fsb might work, because it seems that any time i go over the 230-233 fsb mark with the memory prime 95 will almost immediately return an error within like 2 minutes.

I'm thinking about getting the Antec 900 case from newegg while it has free shipping, what do you guys think about that case?
 
If going over 230fsb cause a problem every time, It's not your temperatures... 53c is not too hot for those chips, upwards of 58 or so is.
 
I had always hoped that because i bought DDR 500 that it would not be a limiting factor in an overclock, but maybe it is. I'm going to try to drop the memory speed and see if i can go higher with the cpu fsb, because I have seen reports of this 4000+ san diego core hitting 3.0 gig and higher in non water cooling setups.

Before i got the ninja heatsink i was using a thermaltake polo 735, and i think that the cpu did get closer to the 60c mark with full load and still held a 2.8 speed.
 
just1tree said:
I had always hoped that because i bought DDR 500 that it would not be a limiting factor in an overclock, but maybe it is. I'm going to try to drop the memory speed and see if i can go higher with the cpu fsb, because I have seen reports of this 4000+ san diego core hitting 3.0 gig and higher in non water cooling setups.

Before i got the ninja heatsink i was using a thermaltake polo 735, and i think that the cpu did get closer to the 60c mark with full load and still held a 2.8 speed.
Click to expand...

My Geil DDR500 ram would JUST hit shy of 500, but required somewhere like 2.9v to do it.

And, you never know, there could be other factors influencing this... like the interconnect between CPU IMC and your RAM.
 
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