Has my bro's CPU hit a ceiling?

[Firegod]

Hello!

Need some advice please for my bro. His current settings:-

436x8.5 - 3.7Ghz
Mem - 1047Mhz @ 15-5-5-5:2T
333/800 Strap

Voltages
---------
Core - 1.25v
VTT - 1.4v
NB - 1.4v
Mem - 2.1v

My bro is running a DFI P45 mobo with an Intel Q9550. The memory is G.Skill PC2-8500 (1066Mhz) DDR2 (2x2Gb).

The problem we are having is that MemTest is reporting errors, yet we can get into Windows up to 3.9Ghz. What can we improve to make this stable, the memory is actually underclocked very slightly so the MemTest errors are a concern, but could it be perhaps voltage related. I think the CPU could perhaps be the culprit here only at 1.25v?

What is the recommended voltage for these CPU's?

Thanks for any pointers!

 

[Voxination]

1.25v seems a bit low, although the Q9550 is a 45nm CPU.

Have you tried going to about 1.28 vCore? Would your temperatures allow you to do this?

 

[JonJ678]

How does the memory do running at stock speeds, with the rest of the system also at stock? Current thoughts are that the memory is damaged

Your northbridge voltage is far higher than I'd expect it to need, and is getting to the point of being damaging if on air. The intel quads need the correct voltage more than they need excess, lowering this to 1.3V or so may also solve the problem. Has it been carefully overclocked so far, only raising the northbridge when nothing else helps and this does?

 

[Firegod]

1.25v seems a bit low, although the Q9550 is a 45nm CPU.

Have you tried going to about 1.28 vCore? Would your temperatures allow you to do this?

I thought about going for 1.3v and see what happens. He has it watercooled so I don't see this as being a problem, I will try that out. Thanks.

 

[Firegod]

How does the memory do running at stock speeds, with the rest of the system also at stock? Current thoughts are that the memory is damaged

Your northbridge voltage is far higher than I'd expect it to need, and is getting to the point of being damaging if on air. The intel quads need the correct voltage more than they need excess, lowering this to 1.3V or so may also solve the problem. Has it been carefully overclocked so far, only raising the northbridge when nothing else helps and this does?

That's what I'm also wondering, is the memory duff. I'll try saving the current OC to the CMOS Reload section and then load the defaults and manually set the RAM speed; see what happens.

Yeah the NB was one of the areas that we just ramped up to 1.4v when we were having the initial problems, as I thought perhaps the higer FSB speeds were causing it to crap out. We can lower this to 1.3v if you like.

 

[JonJ678]

Well, its entirely up to you what you do with voltages. 1.4V on my P5Q made it very unstable whereas 1.3V was solid, more voltage isn't always better. Fsb termination/vtt is another one.

What point was it last stable at? I personally overclock very slowly, but it's possible you've jumped straight in at 3.7 and that's fine too. Until it's unstable and you can't work out why

45nm quads seem to be rather harder to clock than 45nm dual cores, my e8400 just went faster and faster the more voltage I offered it. q9550 was a nightmare, never got it stable much above 3.8

 

[Firegod]

Well, its entirely up to you what you do with voltages. 1.4V on my P5Q made it very unstable whereas 1.3V was solid, more voltage isn't always better. Fsb termination/vtt is another one.

What point was it last stable at? I personally overclock very slowly, but it's possible you've jumped straight in at 3.7 and that's fine too. Until it's unstable and you can't work out why

45nm quads seem to be rather harder to clock than 45nm dual cores, my e8400 just went faster and faster the more voltage I offered it. q9550 was a nightmare, never got it stable much above 3.8

Hi, thanks for the help.

Yeah we upped it quite slowly. I'll have to double check with him but I think we did it in jumps of ~50Mhz. 3.6/3.7Ghz seems to be where we are having issues.

I think things to try are going to be:-

- Up CPU voltage -> 1.3v
- Perhaps check the TRFC value on the RAM, not sure if this has been left on AUTO but I know it needs to be around 45+ mark for 4Gb RAM.
- Perhaps check out the GTL settings as well, which I know tie in with the VTT voltage for the CPU.

Oh, and possibly most importantly, try everything at stock and see if the RAM is OK!