How poor is this Phenom II overclock and can I do anything to improve it?

L

Luca Rescigno

Weaksauce
Joined
Nov 2, 2003
Messages
70
Just got a Phenom II X3 720BE. I heard it can overclock to 3.5 pretty easily so I started playing around with the multiplier (my motherboard, btw, is a Biostar TA790GX 128M).

I've been using HyperPi to test and assuming that's a reliable indicator of stability, this thing is a really poor overclocker.

Here's what I can run with three threads and not cause HyperPi to crash (calculating to 1M by the way):

3.2 GHz @ 1.35v
3.3 GHz @ 1.5v

3.3 GHz doesn't work at 1.35v or even 1.45v. I had to bump it all the way up to 1.5v for 3.3 to work, and taking it to 3.4 at the same 1.5v caused HyperPi to crash. Am I stuck with 3.3 GHz? I was hoping to get at least to 3.5 but I guess I can't count on that.

Another thing, I am using Vista 64-bit but HyperPi has an option to disable audio (which apparently causes instability in Vista).

Is there another bench I can run to test stability? I guess Prime95 for hours at a time is an option. I'm a little skeptical of HyperPi just because it shows problems so quickly. But of course it's also an attractive option for the same reason.

Lastly, would I stand a chance of improving my CPU overclock if I underclock my RAM and HT link, or even my entire FSB and just raise the multi to compensate? Or would that not help?
 
check and see if you have ACC turned on in the bios.. just to see if it helps.. though most have said it doesnt make a difference..

also check what your final voltage is after vdroop.. just because your bios shows 1.5v in the setting doesnt mean its actually running at 1.5v..
downclocking the FSB/ram/HT links not going to really change anything.

but you should be around 3.5-3.6ghz at 1.5v (counting vdroop)

or take a screen shot of cpu-z and post it w/ your current bios settings used when you took the screen shot.. i might be able to help you more after that..
 
I actually tried turning on ACC when I first set up this CPU because doing so is supposed to potentially unlock the fourth core. Unfortunately, with mine it caused it to not post, so I have to leave it off.

Anyway, I accounted for vdroop and checking CPU-Z it's now doing 1.504v. And at 3.4 GHz it still causes HyperPi to stop working within seconds of pressing the start button. I know HyperPi at least has the potential to work because I ran it several times at lower clocks without a hitch.

I'm wondering if I was just cursed...
 
I wonder if its just a weak board/cpu.

Using my M3A78-T (790GX+SB750) with 4gb or 8gb of ram, I can't get my 940BE @ 3.2 even at 1.4v just multiplier only using Prime95 over an hour, of course at 1.45v 3.6 boots fine but usually craps out within 10mins. Onboard video disabled, ACC disabled, CPU Tweak Disabled, unganged memory.


Have you tried bumping NB-HT voltage to 1.3-1.35? Might stabilize a bit better.
 
jimbo6846 said:
why not just run Prime95 or Orthos and see what happens?
Click to expand...
Doing that now. Before I left for work I started my computer running Prime95. Setting is 3.2 GHz and 1.4v (turns out 3.3 @ 1.5v still isn't totally stable; HyperPi crashed after a few minutes rather than a few seconds). Earlier I was running it at 3.2 at 1.35v, but I bumped it up to 1.4v to be on the safe side and if it's still running Prime95 when I get home then I know it's stable.

RogueTrip said:
I wonder if its just a weak board/cpu.

Using my M3A78-T (790GX+SB750) with 4gb or 8gb of ram, I can't get my 940BE @ 3.2 even at 1.4v just multiplier only using Prime95 over an hour, of course at 1.45v 3.6 boots fine but usually craps out within 10mins. Onboard video disabled, ACC disabled, CPU Tweak Disabled, unganged memory.

Have you tried bumping NB-HT voltage to 1.3-1.35? Might stabilize a bit better.
Click to expand...
I'll try those when I get home.

Thanks for the help everyone.
 
Wow, that worked! I did the following after I got home:

- Increased the HT voltage from 1.2v to 1.3v
- Increased the NB voltage from 1.2v to 1.3v
- Disabled the onboard video (not using it right now)
- Set the CPU for 1.475v (CPU-Z reports 1.44v) and 3.3 GHz

I did HyperPi to 1M places and it passed, so then I ran Prime95 for about five hours and when I got back the tray icon was still green. Perfect! I'll have to try for 3.4 GHz next... I wonder how far those other changes will go towards increasing my OC ceiling? I guess I could also try for 3.35 GHz and drop the RAM/HT dividers but that seems like a waste for just 50 MHz.
 
I'm running the same setup as you and I am 4hr+ Orthos stable @ 3.8Ghz. Tried to unlock the 4th core as well and could not even boot Windows, it will boot and tell me I have 4 cores but thats it. But I am liking this proc, though it's still slower then my E6750@4Ghz on a Asus P5E especially on the memory scores. But if I tweak this system enough I may get close.

- vcore @ at 1.55
- HT @ 1.5v
- NB @ 1.5v

Have not played with anything else like ram timings and fsb speeds yet. My ram is only running 800mhz (GSkill 1000mhz).

Anyone know if I up the HT link from 1600 to 2400, that I'll see a difference?
 
dont waste your time changing the ram/HT dividers.. theres no reason to.. even a 50mhz overclock using the FSB you shouldnt have to touch the ram or HT timing..

and digitalpro5 you will see a difference in the benchmarks going from 1600 to 2400 on the HT link if your motherboard supports.. the AMD HT = intel FSB.. basicly the easiest way to describe it..

luca just work your way up .5x multi at a time.. your board should allow you to do that.. 100mhz jumps instead of 200mhz.. easier to pinpoint where the voltage changes need to be..
 
You won't really notice any difference in the HT overclock, unless you are using multiple video cards. The amount of bandwidth it provides at stock rarely fully utilized.
 
You must log in or register to reply here.
Back
Top