Overclocking core i5

[jwalkermed]

Sorry I'm asking so many questions, but I have one question about OC. Before I decided to the hackintosh, I had my core i5 OCd (i have after market cooling) and completely stable with good temps. Well I tried to go back to that configuration in the bios to OC my hackintosh. I ran geekbench after I did this and my marks went from 7600 to 4600? Is there something special you have to do to OC a hackintosh. I like to OC because the i5 is such an overclockable chip and I have the headroom.

 

[cbooty]

Hey jwalkermed:

I am by no means an expert but I can tell you that I tried overclocking my hackintosh to the greatest extent possible without increasing voltages just for testing purposes and I saw steady increases in my Geekbench scores. In fact during testing the best score I managed with 4gb of ram was a little shy of 10,000. I don't really like to push the proc that far however so I run 2.88ghz (with Turbo enabled) 1600mhz ram and I use Tonymac's speedstep DSDT for some energy savings. This returns a score of approx. 8,000 which is pretty solid. Tonymac did mention that overclocking a hackintosh can often result in worse geekbench scores and from my experience I can only assume voltage increases may cause this?

 

[jwalkermed]

Hmm.. well I bumped the voltage on my ram to run it at it's spec of 1600mzh. I also enabled load line calibration which can mess with voltages but I didn't manually tweek the cpu voltage. Just tweeking the base clock and multiplier. I did turn turbo and all that stuff off though. Guess I'll just have to test different settings.

 

[jwalkermed]

Okay I found out what was lowering the GB score. If I disable EIST (speed step) on my MOBO my marks get really crappy. Wierd because I don't have the speed step code in my DTST. But if I leave it on and OC then no problem. I just clocked my i5 to 3.6 and bumped my memory up a bit and got 10000. I don't know If I going to stay with this though because I'm not sure I really need the power right now.

 

[cbooty]

Glad you got to the bottom of it - and it looks like your results are similar to mine. I should mention that I do have a voltage increase for my ram to meet specs from OCZ. I believe ram is set to 1.64 volts. Otherwise like you, just playing with multipliers (and I have a stock cooler so I can't push it too far)! Incidentally I do use Tonymac's speedstep DSDT and it seems to have no detrimental effect.

 

[stingray072]

I'm curious about the speedstep part because all the info I saw about overclocking said to make sure to disable speedstep first. Whats the reason for this if you're able to use it fine....is this dangerous for the proc at all? Thanks

 

[jwalkermed]

From what I understand the reason overclockers like speedstep disabled is because it throttles your CPU. Most OCers don't want their cpu throttled ever. Also it can cause instability at high end OCing from what I've read. As long as you put your machine through stress and it is speedstep should be fine.

 

[stingray072]

From what I understand the reason overclockers like speedstep disabled is because it throttles your CPU. Most OCers don't want their cpu throttled ever. Also it can cause instability at high end OCing from what I've read. As long as you put your machine through stress and it is speedstep should be fine.

Great, thanks for the info. Any recommendations for programs that stress in Snow Leopard?

Also what settings are you guys using to OC that you like (just curious)?

I was definitely going to increase my RAM to 1600mhz, but haven't decided about my other settings. I want to OC a tad but nothing major...want to get the most out of my processor and RAM without decreasing its life expectancy.

Thanks for all the input

 

[jwalkermed]

Let me start with this disclaimer. Overclocking can damage your components if you don't know what your doing. Also it can shorten the life of your CPU/MOBO. How much? Who knows.

With that being said, there are several useful videos on youtube that talk about it and should get you started.

As for stress and stability. A lot of ppl use prime95 to stress (to check stability) and something like realtemp to watch their CPU temps during stress. There is an OS X version of prime 95. I haven't been able to find a temp monitor that works right w/ a hackintosh. I'll just use windows to test my OC config for temps and stability. There is a lot written about using these tools on the net. Google is your friend.

So for me I turned off speed step/turbo and such, bumped up my ram voltage to manufactures spec. And played with my multipliers to get my ram and CPU speed up. Not going to touch my cpu voltage as long as the machine is stable. I also have a corsiar h50 cooler which is better than stock so I have some headroom for overclocking.

Again, don't attempt this if you don't know what your doing.

Attached is my geekbench score. I think I can live with that for an ~ $800.00 build.

Screen shot 2010-01-19 at 11.55.23 PM.png

 

[cbooty]

I think I'm on the same page as jwalkermed with regard to overclocking. I run a very modest overclock to get the most out of my equipment while still utilizing speedstep (throttling) for energy savings and turbo for that speed bump when you need it. Also I don't want my fan running like crazy or my processor near its thermal limit. The settings I use of the top of my head (currently at work) are 18X clock, 160 BCLK, with RAM set to manufacturer recommended settings of 8 8 8 24, 10x with extreme and a voltage of 1.64 volts. These settings should result in a final clock speed of 2.88ghz and your ram at 1600mhz. Again, a very modest overclock that pulls in Geekbench scores of around 8,000 with 4gb of ram. If I get a chance tonight I'll double check my bios settings and provide more info if anyone is interested....