Does the fourth core on my Phenom X4 9750 just suck?

pantsaregood

Senior member
Feb 13, 2011
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I've manually locked cores and ran the CPU up to 3.2 GHz on cores 1-3 with the fourth core disabled. Upon activating the fourth core, Windows won't even boot.

Anything above 2.8GHz on the fourth core seems to cause severe instability, even at absurd voltages: I've tried pushing the VCore as high as 1.6v (which would probably fry an Agena in no time), and it still failed at any sort of stability.

RAM speed, HT, and Northbridge are all running at slowest possible speeds. I'm pretty sure the core just sucks.
 

WhoBeDaPlaya

Diamond Member
Sep 15, 2000
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It's a pretty common occurance that you need more Vcore to get the same OC out of an unlocked chip.
Not always of course - I unlocked all six of my X3 740 BEs and most of them OC'ed the same (voltage, speed, etc.) whether they were running as X3s or X4s.
 

pantsaregood

Senior member
Feb 13, 2011
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It's not an unlocked chip. Its a Phenom X4 9750 that I DISabled cores on to check if one was limiting my overclock. It runs at 2.8GHz stable with all four cores active at 1.35v. With only cores one and four enabled, it won't run 2.93GHz at 1.6v.
 

WhoBeDaPlaya

Diamond Member
Sep 15, 2000
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Oops, my bad. Just answered another X2 555 BE thread and have no idea why I thought your chip was a non-X4 :S
 
Dec 30, 2004
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It's not an unlocked chip. Its a Phenom X4 9750 that I DISabled cores on to check if one was limiting my overclock. It runs at 2.8GHz stable with all four cores active at 1.35v. With only cores one and four enabled, it won't run 2.93GHz at 1.6v.

Use PhenomMSRTweaker and you can control each core independently. Note that it doesn't know what voltage you've set in the BIOS-- only what the stock voltages are! So if you've changed the BIOS voltage, then +0.25v from stock in the software will be +0.25v from the BIOS voltage that you've set.
 

Martimus

Diamond Member
Apr 24, 2007
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Probably. But one nice thing about the Phenoms is that you can clock each core at a different speed, so you should be able to over clock the rest of your cores and leave that one at 2.8GHz.
 

pantsaregood

Senior member
Feb 13, 2011
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No luck with the program suggested. Windows crashed upon booting.

Messing with AMD Overdrive again.

Cores 1 and 2 at 3.2 GHz. 3 and 4 at 2.8 GHz. Crashed at 1.42v after 30 minutes of OCCT. Trying 1.44v now.

I can't get my system to boot with the Northbridge running above 2.13 GHz. I've tried overvolting both "CPU-NB" and "Chipset," but neither seems to accomplish anything. I don't know that it isn't stable. It seems like my BIOS just won't allow it.
 
Dec 30, 2004
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well you've got a 9750. The Phenom 1's sucked at overclocking all around. 3Ghz was about all they could hit.
 

john3850

Golden Member
Oct 19, 2002
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Cores 1 and 2 at 3.2 GHz. 3 and 4 at 2.8 GHz. Crashed at 1.42v after 30 minutes of OCCT. Trying 1.44v now.
No game is going to pull as much load as OCCT does.
Maybe the mb has a temp. problem.
I would first have fans on NB and on any MOSFETS close to the cpu.
 

BD231

Lifer
Feb 26, 2001
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Cores 1 and 2 at 3.2 GHz. 3 and 4 at 2.8 GHz. Crashed at 1.42v after 30 minutes of OCCT. Trying 1.44v now.
No game is going to pull as much load as OCCT does.
Maybe the mb has a temp. problem.
I would first have fans on NB and on any MOSFETS close to the cpu.

Yeah those chipsets get pretty darn hot and typically only have passive cooling. When I got this GTX 460 I started having crashing issues and it turned out the radiant heat nailing the north bridge was limiting my overclock.

Replaced the tim, streched the springs and added a tiny fan. No more crashing. I'd aim for 3ghz on all cores though.
 

WhoBeDaPlaya

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Sep 15, 2000
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Those VRM chips can handle the temps. I've measured them on my TA870+s hitting 80C pushing an unlocked X3 740 BE @ 3.8GHz running Prime95.
 

pantsaregood

Senior member
Feb 13, 2011
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Using a Biostar TA790XE. No Chipset/Northbridge sensor, as far as I can tell. Motherboard temperature usually shows up in the mid 40s while the CPU is under load. Trying 3.06 GHz on cores 1-3 with core 4 at 2.8GHz right now. Stable so far for 30 minutes.
 

BD231

Lifer
Feb 26, 2001
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Those VRM chips can handle the temps. I've measured them on my TA870+s hitting 80C pushing an unlocked X3 740 BE @ 3.8GHz running Prime95.

I was speaking on the northbridge sink not the VRMs. This is good to know though, I accidentally bought a value board that does not come with VRM cooling of any kind and had to put on my own which aren't quite as robust as some of the overclocking boards.

Nice OC :thumbsup:. I've played with a few 740s/720s and got them to 3.6/3.7. The740's are definitely more responsive to voltage so you got in on a good model.
 

john3850

Golden Member
Oct 19, 2002
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As the heat leaves the MOSFETS it can get trapped by a water block or hsf bracket and in turn adds some extra heat to the cpu.