AMD Phenom 940 OC

sir-les-mp · 21 Mar 2010 at 23:51

After the last few days of nothing but constant troubles with my system and reinstalling windows, ive finally seem to have a decent OC of 3.72 Ghz on my cpu.
I have now finally also installed the last of my hardware and im looking to test my OC for stability.
ive already got CPUID and Coretemp running and have downloaded three differrent stress testers. Prime 95, OCCT & Orthos.
I know i need to run the test for a good 8 Hours or longer to be guarenteed stability.
What i would like to know out of the three stress testers ive downloaded which would be the best to test an AMD Cpu.
Once ive sure the OC is stable i will be using the system a lot of the time for F@H using the SMP Client, in between the odd gaming session.

eddyc · 22 Mar 2010 at 10:10

If you absolutely must be completely stable I would run more than one stress test. Maybe prime blend for 12 hours and then any other.

sir-les-mp · 23 Mar 2010 at 08:44

Well what a waste of two days that seems to have been.
It seems no matter what settings i choose in the bios to clock my cpu it will not run stable.It even frooze after a 4 Hour occt stress test at stock settings although it advised the test completed without errors.
There is something in my system that is preventing me from clocking my cpu past stock, even the tried and tested upping the multiplier seems to fail once i start stress testing the cpu.
I can defineatly rule out heat as with all the testing i did the highest temp i got at 100% load was 49c as my cpu is watercooled.
I also figured out any setting i used that took the cpu above 3.75 Ghz failed to boot into windows.
I thought i had found the sweet spot for the cpu at 3.6 Ghz but after hours of tessting with both OCCT and Prime 95 it fell over when i Ran OCCT for more than the auto setting of 1 Hour.
which leads me to belive its my mobo causing the instabilities

Current setup
AMD Phenom II 940 BE
Asus M3a79-t Deluxe
4Gig Kingston Hyper-X 8500 Memory
Maxtor 320Gig drives in raid 0 for system
Tagan 1100Watt PSu
Main GPU is a BFG GTX280

Cooling D-Tek Fusion V1
Laing D4 Pump
Black Ice 120MM Rad with Zalman Reserator as RAD/RES

eddyc · 23 Mar 2010 at 10:10

What vcore are you using? If it is still on auto your mobo might have set it too low.

sir-les-mp · 23 Mar 2010 at 11:20

Vcore i started with it at 1.35 i then uppted it to 1.4 at 1 piont i even had the vcore upto 1.475 and still could not get it stable.

eddyc · 23 Mar 2010 at 12:06

Ideas:

memory error: use memtest to check

memory speed causing problem: slow the speed down and run prime blend

remember the cpu-nb speed is 2000 at stock but should be 3x the speed of the memory. i.e. 1600 speed - 800x3=2400 so cpu-nb should be at least 2400.

cpu-nb voltage: stock might be too low. Try upping to 1.35 or so.

rumble291 · 23 Mar 2010 at 15:16

Check your voltages. HT link as well as CPU-NB and I slightly added 0.02 on my NB but don't put too much through the NB.

Another thing is RAM if your overclocking your ram you will need to increase the voltage aswell. Your problem does sound RAM related as if you can run OCCT for an hour thats pretty stable. Your CPU is more likely to be causing problems under 20 mins above that then its more likely RAM. What are your timmings for your ram? This may have a bad affect on your overclocking. My RAM hates 6-6-6-20 timmings but is fine on 7-7-7-24, If i run at 6-6-6-20 I get core errors and when I dont stable on OCCT until my core temps hit 58c then I cancel as instability always occurs around then. Unless your running your system at 100% for a long period of time then I would only run OCCT for an hour or 2. If your after absolute stability then 6-12 hours.

If your temps are below 50c all the time then its deffo not temp related. don't be too scared of upping your voltage just not in big steps like 0.1 you want to go up in 0.02 or 0.04. I normally have my volts set higher rather than lower as after deemed stable you can start trying to relax the volts.

Just on another note... your using the unlocked multiplyer right?

sir-les-mp · 23 Mar 2010 at 16:28

eddyc said:
Ideas:

memory error: use memtest to check

memory speed causing problem: slow the speed down and run prime blend

remember the cpu-nb speed is 2000 at stock but should be 3x the speed of the memory. i.e. 1600 speed - 800x3=2400 so cpu-nb should be at least 2400.

cpu-nb voltage: stock might be too low. Try upping to 1.35 or so.

I did try setting the NB to 2400 as well as upping the HTT to 2000 as mines at stock are 1800.
i did up the cpu -nb voltage to 1.25 as i read the stock voltage for it was 1.175

rumble291 said:
Check your voltages. HT link as well as CPU-NB and I slightly added 0.02 on my NB but don't put too much through the NB.

Another thing is RAM if your overclocking your ram you will need to increase the voltage aswell. Your problem does sound RAM related as if you can run OCCT for an hour thats pretty stable. Your CPU is more likely to be causing problems under 20 mins above that then its more likely RAM. What are your timmings for your ram? This may have a bad affect on your overclocking. My RAM hates 6-6-6-20 timmings but is fine on 7-7-7-24, If i run at 6-6-6-20 I get core errors and when I dont stable on OCCT until my core temps hit 58c then I cancel as instability always occurs around then. Unless your running your system at 100% for a long period of time then I would only run OCCT for an hour or 2. If your after absolute stability then 6-12 hours.

If your temps are below 50c all the time then its deffo not temp related. don't be too scared of upping your voltage just not in big steps like 0.1 you want to go up in 0.02 or 0.04. I normally have my volts set higher rather than lower as after deemed stable you can start trying to relax the volts.

Just on another note... your using the unlocked multiplyer right?

Ram Voltage is at 2.3v as recommended by Kingston
i set the timmings to 5-7-7-27-32 as i read they should help keep them stable in a 64bit system.
As for setting the timmings on the ram i dont have much of a choice with my mobo.
i was looking at setting it at 7-7-7-24 but system wont allow me increase the CL timing that high. And if i drop the speed down to 800Mhz i get even less options for setting the timings manually.

as for the HTT voltage i tried to set it to 1.22 but my mobo will only increase it in steps of 0.1 and not 0.02 so i left that at 1.2v

As for stability i have the system on 24/7 running F@H so im looking for a rock solid stable OC

What really cheese's me off is that i was able to install windows onto the system with it set at 3.6Ghz but it falls on its **** the minute i try loading the cpu to 100%