Can't touch 3.9-4.0 GHz

[cmcghee358]

I'm not at home at the moment so my numbers might be off, going from memory.

I have a 955 BE CR stepping with an H50 on it. I have good temps at stock 29C Idle, 39C Prime 95 @ 1.3 vCore

Considering my low temps I thought I'd play around with the multiplier and try to get close to 4.0GHz

With 1.4 vCore, with 202 HT and an 18.5 multiplier I can get a 3.73 GHz clock.

No matter how much I raise my vCore, I can't get stable on 3.9 GHz.

So my question is, on a BE CPU do I need to do anything else at a higher multiplier to remain stable besides tweaking vCore?

My temps @ 1.5 vCore max out at 55C But I crash about 2 hours into Prime95 Small FFTs

Of course I also drop my HT back down to 200 so I am working exclusively with the multiplier.

 

[JofaMang]

CR stepping? If it isn't c3, you just might have reached the limits of the chip.

 

[cmcghee358]

CR stepping? If it isn't c3, you just might have reached the limits of the chip.

Miscliked the R, I meant its a C3 stepping.

From what I understand, and I most certainly could be wrong, but increase in voltage gives room for more clock. So Im curious why from 1.4 to 1.5 I can't gain any ground on my clock. Im wondering if I need to tinker with anything else?

 

[stridervm]

My suggestion :

- Lower your HT.
-Check your RAM. Or maybe lower your RAM speeds/settings.

 

[JofaMang]

You can try upping your NB and see if that will help calm the chip down. It doesn't work for everyone, but it may be what you need atm.

I have a similar Vcurve on my 965. I go from 1.32v@3.6ghz, to 1.4v@3.8ghz, to 1.48v@4.0ghz, and at room temperature, it takes 1.536 to run 4.2ghz. The cpuid validation in my sig was only accomplished with very cold winter air breezing over my Mobo. There is a variation from chip to chip (they are all different, even if they are exactly the same) when it comes to the voltages needed to stabilize certain clocks. There is also the motherboard to think about, as how the mobo performs will also effect these states.

If you can't get it stable no matter what past 3.8, it could be the limit of the chip, it could be the motherboard holding you back, or it might even be your memory. It is hard to say, but regardless of what is holding you back, that just might be the limit of your setup.

 

[cmcghee358]

Best answer selected by cmcghee358.

 

[4Ryan6]

Hi cmcghee358,

My OC goals are to arrive at a rock solid 24/7/365 OC, of which I have my 965 at 4.0G @ 1.424Vcore running a 20 multiplier.

I've gotten my best results OCing AMD Black Edition CPUs, by manually setting the memory voltage and timings to the manufacturers specifications and leaving everything else in spec like the HT, if you don't manually set those memory settings you will have problems when you raise the multiplier.

You increase the CPU voltage to match the multiplier increase, however if anything is out of spec regarding other spec parameters you'll get crashing that may not have happened if everything else had been within specifications.

Meaning you could have already hit on the perfect voltage to run a certain multiplier increase but the other settings not being within spec caused a crash, which makes you assume no Vcore setting will accomplish your goals when something else may be hindering you from reaching your goals.

You should easily reach 3.8 with your 955 that's only a 600mhz increase, and with your temps you should be able to reach 4.0G stable, each CPU is different quality and each M/B has its on plus's and minus's for OCing, but at least try what I'm telling you here, it works for me.

My AMD BE CPU OCing track record is, an X2 5400+, a Phenom X4 9950, a Phenom 2 940, and my present BE 965, so this is not my first AMD BE OC, I hope this helps you reach your goals. Ryan

 

[JofaMang]

Hi cmcghee358,

My OC goals are to arrive at a rock solid 24/7/365 OC, of which I have my 965 at 4.0G @ 1.424Vcore running a 20 multiplier.

I've gotten my best results OCing AMD Black Edition CPUs, by manually setting the memory voltage and timings to the manufacturers specifications and leaving everything else in spec like the HT, if you don't manually set those memory settings you will have problems when you raise the multiplier.

You increase the CPU voltage to match the multiplier increase, however if anything is out of spec regarding other spec parameters you'll get crashing that may not have happened if everything else had been within specifications.

Meaning you could have already hit on the perfect voltage to run a certain multiplier increase but the other settings not being within spec caused a crash, which makes you assume no Vcore setting will accomplish your goals when something else may be hindering you from reaching your goals.

You should easily reach 3.8 with your 955 that's only a 600mhz increase, and with your temps you should be able to reach 4.0G stable, each CPU is different quality and each M/B has its on plus's and minus's for OCing, but at least try what I'm telling you here, it works for me.

My AMD BE CPU OCing track record is, an X2 5400+, a Phenom X4 9950, a Phenom 2 940, and my present BE 965, so this is not my first AMD BE OC, I hope this helps you reach your goals. Ryan

He handed out the best answer a little early me thinks, hah.

 

[jeyd02]

it seems. lmao

 

[cmcghee358]

it seems. lmao

Yeah I sure did, I PM'd 4ryan6 and thanked him, and also asked for clarification. I guess that'll learn me to select a best answer so early...

 

[4Ryan6]

Yeah I sure did, I PM'd 4ryan6 and thanked him, and also asked for clarification. I guess that'll learn me to select a best answer so early...

So far the only real problems I see is OCing 8G of mismatched memory modules between your Value Select and XMS modules, its difficult enough to get 4G to cooperate together much less 8G, obviously you're running a 64bit OP/SYS of which I don't see mentioned yet.

And make and model # of your M/B?

and also asked for clarification

What I posted couldn't be simpler IMO, you set the memory timings and voltage manually so there will be no fluctuations that the M/B itself may automatically apply at the wrong time, you leave everything else within specification like you mentioned your HT at 202 set it at 200.

Keep everything else within its speed specification window, that only leaves increasing the CPUs supplied voltage Vcore to match the increased multiplier you're trying to run, once you discover the perfect voltage for the raised multiplier you're attempting to run, everything else stays within specification.

I really don't know any simpler way to explain it, there are always variances though, as my M/B has 2 different CPU voltage adjustments and yours may not, without even knowing the M/B you're running, I have no idea what the differences may be between our differing hardware.

No offense but as a moderator here at THGF I just don't have the time, to take you by the hand and walk you through OCing your computer, so I'm trying to give you as much information as possible in the time I have to spare here, I hope you understand that.

The simplest O/C you'll ever do is an AMD BE unlocked multiplier CPU, but most older AMD strategy is raising the FSB and trying to achieve their O/Cs that way, when increasing the AMD CPUs multiplier increases the negative effects of raising the FSB and the instability.

Click on my CPU-Z validation banner and look at my settings, that was not a shot in the dark O/C that's what I'm running right now.

You can also check out my response in this thread > http://www.tomshardware.com/forum/258565-29-serious-needed#bas