Is there a guide to undervolting and/or downclocking in OSX?

Hey all,

My MBP 13 is coming this Monday. I've learned over time how to undervolt CPU in Windows.

Now my question is, is there a guide to undervolting the CPU in OSX? I understand that CoolBook can be tuned to downclock the CPU, reducing its performance when the extra power is unnecessary.

Thanks

 

To be honest, you shouldn't need to do that.... whay do you feel inclinded to?

The mbp 13" is a great power horse when needed but when idle, its battery life is great no need to make it slower in my opinion.

 

I've had mixed experiences with MBP temp. It seems as with cars, the temps tended to vary by large margins. I've always been into keeping the CPU temps on my PC laptops super low and if possible, I'd like to do the same with my Mac.

Chalk it up to the control freak inside me.

 

Well I just got mine yesterday (MBP 13) ... I haven't tried pushing it to the limit but from tinkering with settings and extensive installations, the machine ran cool.

You're not really going to be doing yourself a favor by downclocking this machine, just my opinion.

 

I must admit, when pushing the laptop to extremes playing games on windows or encoding the temps reported hit about 85-90oC; quite warm, but I'd imagine that apple knows that already and has taken precautions so that it doesn't wear components out too easily. The processor will also throttle automatically when it gets too hot; i.e. when waiting for the fans to ramp up which I've seen a couple of times.

The cooler the better is probably right but the laptop is made of metal so heat will transfer and seem hotter to touch also, mine does sometimes. Also I've used a leather cover from the start and noticed no diff in temps, but its air vent isn't obstructed so thats ok.

 

I'm more interested in learning how to undervolt more so than downclock. I guess I should've made that clear.

 

Hmmm, once again, it's just a matter of personal preference. Lowering the voltage would not only lower the heat levels on the CPU but also on the GPU. I'm not entirely confident the CPU will remain at optimal levels as I'm currently typing on an undervolted laptop that's running the P7450, which after undervolting has been shown to occasionally hit 29C in this warm weather without any sacrifice in performance or stability. Doing this undervolt lowered my GPU temps and helped my processor go from "acceptable" temps to "optimal."


I've heard that "____ authority figure knows what's better for you, so do as he/she says" line more than once in the past, and let me tell you...it's not always true. Having a seamless hardware/software integration has its benefits. But it also has its own pitfalls. Lack of customization and tweaking that Windows users have is one of them.

 

I'd like to see what others can come up with; I think it would be good as a last resort for those with heat issues and maybe me when using the laptop normall i.e. not encoding, just to see how much more I can get out of it.

 

See? It's just about getting the best of both worlds, PC and Mac! There's nothing more satisfying than seeing your GPU temps at 44C and your CPU temps at below 30C! I'm no overclocker. But even though I bought Applecare Protection, I'd like to keep my laptop up and running with few problems as possible so that 3 years down the road come time to upgrade, I can say that I kept the same laptop for more than 2 years with no problems!

My Dell Vostro's screen died. 3 months before that, my GPU had fallen victim to the curse of the 8600M GT's design defect. I was too young and dumb 2 years before that time to have known better than to cheap out on a warranty.

 

I'll be getting a 15" in few weeks, and I am also very interested in undervolting. Felt my friend's i5 MBP get toasty. I don't need too much processing power so undervolting would be great to lower temps + increase battery life.

 

@ butcom

As I understand it, undervolting won't reduce your processing power. All it does is attempt to run the processor at the same speed using a lower voltage. Underclocking would drop the power. I spec my laptops to the power I want so I would undervolt but not underclock.

 

^ that is correct.

 

I'd be careful with undervolting though. You have to have the EXACT right voltage settings or else it will crash.

I tried undervolting on my old Dell and the settings were a tad too low and it just froze. Luckily I didn't set it to "AUTOMATICALLY START UP" when Windows starts or else it would be a never ending nightmare.

 

As long as its not too low, it'll be fine. You don't have to get the exact right voltage settings.

 

What he said. There is a thread on undervolting in the hardware forum. Its for windows but most of the cautions and advice should be applicable. Basically drop the voltage to where you get crashes or freezing then raise it a couple of notches for safety and you're set. Its generally useful to run some sort of benchmark or stress test when undervolting to make sure you've found the correct limit.

 

Ah true, but generally it will make higher speeds unstable. I will likely be undervolting + underclocking to retain full stability. Undervolting + turboboost is asking for trouble. Lots of stability testing will need to be done...

The only software I found that does this is Coolbook but there is no version for Core i5/7...

 

No it won't. Undervolting is done per multiplier. You can enable higher voltage for higher multiplier. If it's unstable at higher speed, it simply means you haven't properly undervolted your processor.

 

Ah depends on the software support. When they just came out, some X58 chipset desktop motherboards for the i7 just set the voltage constant if it was not the default. Default behavior was however scaling voltage with frequency.

Whatever the solution is for OSX though should certainly scale voltage/frequency together. Finding that scaling ratio may not be trivial though.

Anyway back to the thread topic, has anyone found a way to do any of this under OSX with the new Core i series Macbook pros???

 

I downloaded and installed CoolBook (similar in concept to RMClock, for you Windows undervolting fans, but not quite as sophisticated); it dropped my temps about 8-9 C in OSX. I also installed RMClock in my Bootcamp XP and got good results there too.

 

Coolbook doesn't work on Core i5/7 macbooks

 

did you check multiple temperature sources... and not only use Coolbook's temp?