Core i5 750 Overclocking yields low scores.

[intrus22]

Hey guys,

I got 10.6.3 and when i try over-clocking i get low 4000's on geekbench and if i go back to stock 2.67ghz, 1333mhz ram i get 7750 average score on geekbench.

I over-clocked using Profile1 on my BIOS, which sets core to 2.87ghz and Memory to 1600mhz and i get low 4300's on Geekbench 64bit.

I also tested overclocking manually, keeping memory at 1333 and cpu at 3.33ghz and i get 4000's still on geekbench

Any idea guys??? Temps dont even go over 60 when testing on 3.33ghz. its liek something its stopping it from going up.

 

[Jocelyn84]

I remember this happening a few months ago (when I first setup my system), but I totally forget why.
Change your memory to 1600 in your SMbios.plist and I'll start thinking.

 

[intrus22]

Hey Jocelyn thank you.

You do this by adding:

<key>SMmemspeed</key>
<string>1600</string>

Correct? but isn't this just for cosmetics? what will that do ?

Note that my ram/frequency changes properly when i make changes to bios; in other words, it updates ok on "about this mac".

 

[Jocelyn84]

Yeah ignore what I said about the edit. This is really bothering me, because I know I've solved the same issue.

 

[intrus22]

Lol dang, btw what would be an easy way to see if speedstep is enabled on the mac.

Thanks

 

[adamsmasher]

Lol dang, btw what would be an easy way to see if speedstep is enabled on the mac.

Thanks

There's only one way to check if Speed Step is working: boot into 32-bit mode and run MSR Tools. You'll see your processor speed stepping down if it's working.

 

[intrus22]

Thanks adam, imma give it a shot.

 

[rich]

i noticed that with SpeedStep enabled overclocking caused my CPU to run at the lowest downclock speed resulting in a miserable Geekbench. i then worked out that enabling EIST (from auto) allowed speedstep and overclocking to happily coincide (probably common knowledge in the overclock thread).

also it is advised to enable all the advanced CPU options when overclocking, this brought my CPU temps down a few degrees, and to disable turbo boost if trying a max overclock.

 

[aaron]

Hi guys,

Did you ever figure this one out? I'm having the exact same issue with an i7-860 on a GA-P55M-UD2, running 10.6.2, 8Gb of 1600 DDR3. I've changed the system clock to 160MHz and the CPU speed is up to 3.36GHz from 2.8GHz. Strangely, in addition to much lower Geekbench scores, the CPU temp has actually gone down so something appears to be holding the speed back. Any ideas would be greatly appreciated.

Aaron

 

[intrus22]

Hey,

I got it working perfectly fine now; Thanks Rich

Ok first be sure you have all CPU Features on ON except for Turbo mode as well as EIST (from Auto to ON); i have the speed-step enabled DSDT.aml and also very important be sure your smbios.plist is setup for imac not mac pro i had it as a mac pro and my scores were bad.

Like Rich said, set most of your bios option manually, don't let most options "AUTO" specially "EIST".

I've included a zip with my extra folder, i have core i5 so be sure to make the change in the "SMcputype" field of smbios.plist to match your core i7 before restarting your system.

Be sure you are running Bios F8 and not a low version.

Just be sure you go over your CPU features on the BIOS and all of them are on except for Turbo mode

Good luck!