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Folding on an overclocked Sandy Bridge question!

post #1 of 5
Thread Starter 
Hi guys,

I own an Intel Core i5 2500k on a DZ68DB motherboard with which I fold proteins 24/7 with Folding@Home. Since it uses all cores at 100% all the time, overclocking it would be a big benefit. However I have tried many combinations of overclocking options on this board and managed to make the core multiplier go from x33 to x47 (which makes my processor work at 4.7 GHz), but this only happens for, in average, one minute before the processor reverts to x33 and stays this way from then on.
My dad wishes to change his computer, so I am thinking of this: Give him my current motherboard and buy an ASUS or ASRock motherboard with better overclocking capabilities than Intel's. However, I am not sure if the fact that it reverts to x33 after a minute is a problem of the Intel mobo, or it's an inherent behavior to the processor that happens regardless of the motherboard used. Being able to fold at x47 the entire time would justify me buying another motherboard and giving mine to his, but if the mobo makes no difference I'd rather keep my current board and buy a cheaper one for him instead.
Heat is also not the issue, as I have a Hyper 212+ heatsink and the reverting back also happens at lower multiplier settings.

So, is anyone here with a Sandy Bridge processor able to constantly fold, or run prime95 or other processor stress tests, at high turbo multipliers without it reverting back?

Thanks!
Edited by Nantes - 1/27/12 at 2:49pm
post #2 of 5
Could be that turbo is only raising one core to x47, while the main CPU ratio is still x33. There should be a setting in the BIOS that dictates what cores turbo acts on, can't remember what it's called, but it should have a setting called 'all cores', or something similar.
post #3 of 5
Thread Starter 
Quote:
Originally Posted by Goof245 View Post

Could be that turbo is only raising one core to x47, while the main CPU ratio is still x33. There should be a setting in the BIOS that dictates what cores turbo acts on, can't remember what it's called, but it should have a setting called 'all cores', or something similar.

I haven't seen any such setting. My settings are as follows:

Processor C-states: Disabled
Intel Speedstep: Enabled (required for Turbo Boost)

CPU Voltage Override Type: Dynamic (can choose Static or None, I tried putting it static at 1.350V but this seems to cause the processor to work at x16 rather than x33 when all cores are stressed)
Processor Core Voltage Offset: 0.05 V

Max non-turbo Ratio: 33 (if I change this, it reverts back to 33 automatically)
Processor Idle State: High-Performance

Turbo Boost: Enabled (must do so to be able to change multipliers):
TDC current limit overrride (Amps): 120
- Burst Mode Power Limit (Watts): 150
Sustained Mode Time (seconds): 32 (this is the maximum value it allowed me)
Sustained Mode Power Limit (Watts): 150
IGD Current Limit (Amps): 32

Active Core-based Ratio Limits: Disable (while disabled it applies the multiplier I choose to all cores; when enabled I can choose separate multipliers for each core.)
Ratio Limit: 47

Other options such as Spread Spectrum, C1E support, CPUID Max, EIST and QPI Ratio don't appear to be able to be edited in the BIOS for I have not found them.
post #4 of 5
Odd, I think maybe the 'Max non-turbo Ratio' might be the one to change, have you tried turning turbo off completely and then changing this setting again?
post #5 of 5
Thread Starter 
Quote:
Originally Posted by Goof245 View Post

Odd, I think maybe the 'Max non-turbo Ratio' might be the one to change, have you tried turning turbo off completely and then changing this setting again?

I have read that the base cannot be changed, this is a characteristic of the Sandy Bridge processors. Furthermore, I have found this:

http://www.tomshardware.com/reviews/z68xp-ud3-dz68db,2980-17.html

Looks like my mobo will be my dad's after all smile.gif
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