Why doesn't my computer use all 4 cores during certain boots?

From talking to apple yesterday because I was having a similar issue, I have the macbook pro I got late 2010 and mine is the 17” i7 2.66 mhz and 8g of ram. The way they explained it is the computer grabs the necessary memory to run the program you are opening or say movie you are watching online and even though you are no longer using the program it doesn’t always release it from use unless the computer is restarted. They suggested to do a daily restart because I tend to leave my computer running for days, they said this will release all the memory being held but not used. – I hope this helps. I don’t know about you but I got the applecare and have the unlimited techsupport on mine.

This is why I hack my Registry; I don’t want applications staying in memory and taking up RAM after I quit them. I only ever have an issue like that with certain applications (mostly older ones) that don’t support multi-threading.

@jerv That’s just it. The applications support it, they just don’t use it. I know it’s not a ram issue because when I get a “good boot” I just hibernate it whenever I’d normally turn it off, then let windows update every month or so. So the RAM isn’t the issue. Especially considering that I’ll know if the boot is bad immediately after turning my pc on.

Do you have the same problem with OSX or is only in windows? If you see the problem in OSX too then it sounds like a hardware fault. Given that all 4 cores do work on occasion its probably not the chip but it may be the logic board or probably the EFI not configuring things properly.

If you only see it with Windows then it might be an issue with bootcamp.

@Lightlyseared Just a hunch, but I suspect that this is strictly a software issue, and likely a Windows-only issue. This hunch is largely based on the fact that many programs that have versions written for both OSs don’t perform nearly equally; the OS X version of Firefox and the Windows version of iTunes both suck. That tells me that Apple and Microsoft products don’t mix, and it wouldn’t surprise me if Boot Camp was less-than-perfect.

@fortris You only let Windoze update every month? That raises a few other questions…

An application needs to be coded to take advantage of multiple cores. That said, if you’re running multiple single-threaded apps, then the computer should be distributing each of those apps onto different cores to maximize efficiency (OSX does this under the covers). I suspect it’s either a hardware issue, or a bug in bootcamp. As @Lightlyseared asked, can you reproduce the problem when running under OSX?

One option would be to backup your windows partition, wipe it and repartition a new windows drive under bootcamp and check to see if that doesn’t fix the problem. You also might want to look for a piece of windows software that deliberately tests a multi-core machine to verify they are functioning as they should be.

@jerv unless all hell has broken loose Microsoft only releases patches once a month (second Tuesday of the month). I wouldn’t be surprised if it was a bootcamp issue though…

@Lightlyseared Windows almost defines “all hell breaking loose”. While most of my updates happen then, those that don’t are common enough that I treat that schedule as a guideline rather than a fact.

@jerv, @Lightlyseared, @gorillapaws It does not affect OSX, I don’t update windows often BECAUSE of this problem (as it usually requires a restart, and I only use the partition for games regardless), and once again, I’m talking about the same exact applications not using all 4 cores when they normally do so, so yes they’re designed for multithreading.

That screams Boot Camp to me then. I will let you know if I can figure out what it could be aside from a bootloader issue as Win7 is pretty good about multi-core CPUs while Apple is chronically bad with any hardware or software that is not also from Apple.

I think you should create a 2nd windows partition with bootcamp. Load a clean install of Windows 7, and add only your game to it. Test to see if you are able to reproduce the problem in the “clean” install. That should give you more information about how to move forward.

@gorillapaws Forgive my ignorance, but I don’t know how to create two simultaneously. When I use boot camp in OSX it only gives me the option to delete my current partition.

Actually, you are not ignorant; it is not something that is normally supported/allowed. (Limiting features like that is why I don’t like Apple in general, but I digress.) Instead, you have to engage in a bit of trickery that isn’t exactly intuitive. The best procedure I have seen for it is here

Or you could ditch Boot Camp and use rEFIt which I think is a pretty snazzy piece of software, but I would also recommend reading all of the documentation there before you mess around too much.