Q: kernel_task consumes a lot of RAM in early 2011 MBP, sometimes Finder too

So, the integrated graphics chipset seems to take up "wired" RAM, but is NOT part of kernel_task.

If the caption below your Activity Monitor memory pie chart indicates a total of less than the full amount of RAM that is installed in your machine (e.g., in my case, it shows 3.75 GB instead of the 4GB that is installed), the difference is the RAM allocated to the integrated GPU. So that amount is excluded from all four RAM categories — active, inactive, wired and free — and not included in any of them.

Yeah, that's always been my understanding in the past as to how it's worked. But my Activity Monitor shows a total of 4GB, which is why I'm thinking that for these new machines, the amount used by the Intel GPU is included as part of kernel_task (perhaps because it's allocated dynamically, and it would look strange for Activity Monitor's total RAM figure to change).

You may be right. I don't have one of the new machines, and I'm not running Lion either (I haven't heard whether Lion changed this particular behavior.)

My laptop shows 4.00GB… And my friend's older macbook shows 2.00GB. It's been that way since I had it, and IIRC it was the same on my very old macbook. Like I said, the difference between kernel_task and total wired is just over what the graphics chipset is assigned. Plus, his kernel_task is barely larger than what his graphics chipset uses, so that really only leaves room for graphics RAM in the rest of the wired memory.

Hmm. I've got all of these problems - ie MBP early 2011, 13", 2.7 GHz / 8GB.

My K_T is between ~500mb at launch, and up to ~800mb.

I disagree with some people that this is an "academic" chat. My battery life on this MBP is about 3hr max, even when no progs are running. That's really low. I can only believe that this is because so much memory is being taken by the K_T.

Did we come to any conclusion, other than to ignore it (ie Kappy's reply)? If he's right, then I'm starting from zero to understand why my battery (Cycle Count:    84 / Condition:    Normal) is lasting less than otherwise expected.

Bump.

YOU come on.

All the best,

Apple

@rtfromlondon

My battery life is great.

I assume you have gfxCardStatus, and that the integrated graphics are being used?

Of course, the RAM is still a problem.

(Sorry if this is a repeat answer.)

If the kernel on these newer machines is running in 64-bit mode, and on older machines in 32-bit mode, I think this is very likely the reason kernel_task is using up so much more RAM.

Because memory is typically addressable only in 64 bits on a 64-bit system (and 32 bits on a 32-bit system), any reference to an address in memory is now twice as large. I've had plenty of folks try to tell me that the 64-bit equivalent of a 32-bit app won't be or run much larger, but this is simply not the case in the (completely anecdotal) tests I've done.

I think most people would say the big advantage of 64-bit over 32-bit is that it allows the system to directly address more than 4GB of RAM. This should make addressing memory simpler and faster, and I won't disagree with that. But it still requires twice the RAM to store said memory address.

This is a simplification of the issue, and there may be differences betwen the kernel process and other processes I'm not taking into account, so caveat emptor.

This 64-bit issue is not at all unique to Mac, so don't get too upset at Apple about it. I wish all the operating system vendors would be more up front about the likelihood of a 64-bit OS requiring more physical RAM. Apple sets pre-delivery RAM upgrades at ridiculously high prices, but I wonder if it will backfire for them as customers slowly get frustrated with less-than-stellar performance for unknown reasons.

We tried that-booting in 32 bit kernel barely puts a dent in the RAM usage (although it does make a difference).

I really hope these new macbooks can handle 8GB sticks (for 16GB total). Apple advertised 8GB max, but they have been "conservative" with their specs before.

I really hope these new macbooks can handle 8GB sticks (for 16GB total).

They can:

http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_133 3MHz_SDRAM

Absolutely awesome. Last time I checked, they only "theoretically possibly" worked with 16GB (and no one was actually selling it yet). Love how fast technology moves along.

Once 16GB drops below $200, I'll stop complaining about k_t RAM usage. In the meantime...

@ wyager - yup, now using gfxCardStatus (hat-tip to you). Running as "i", of course.

And yup, RAM def a prob.

Question - if I were to do a backup and then totally wipe my hard disk, what sort of kernel_task would I get if I were to be running Snow Leopard / Lion? Presumably this would be high-ish?

I went to see a Genius - this was his suggestion, that way I could see if it was hardware related, or poss something to do with the different software / files on my machine.

So that didn't help your battery?

I think others have tried clean installs to no avail.

BTT... My K_T sometimes seems to run with less RAM usage lately, but not regularly.

I, too, noticed this. I am running 15" 2.2Ghz i7 w/ 8GB RAM..... kernel_task hovers anywhere between 400-800MB, seen it as high as 900MB before.  My guess is this is the VRAM for the integrated GPU...

Intel HD Graphics 3000 allocates a base amount of 384 MB for video and processes at startup. For example, a MacBook Pro (13-inch, Early 2011) with 4 GB of RAM installed has 3.7 GB of memory available to Mac OS X and applications (4096-384=3712). For portables that have been upgraded to 8 GB of RAM, the Intel HD Graphics 3000 will allocate 512 MB of system memory instead of 384 MB. For example, a MacBook Pro (15-inch, Early 2011) with 8 GB of RAM has 7.6 GB of available memory (8192-512=7680)

Source: http://support.apple.com/kb/ht3246

"While some of the kernel_task services will not unload when you quit the processes that have started them, others will, especially if they are managing hardware in the system. For instance, on systems with multiple GPUs, if you use the onboard GPU, then you will see an increase in RAM usage by the kernel_task, but unlike some applications services, if you switch graphics processing back to the dedicated GPU, then the kernel_task will relinquish the RAM it was using for video memory."

Source: http://reviews.cnet.com/8301-13727_7-20091848-263/kernel-task-taking-up-ram-in-o s-x/