Using 15.99gb RAM?!
Hey,
So, my new Macbook Pro Retina came yesterday, its the top 15'' model (2.3ghz quad-core i7, 16gb RAM, 500gb flash based storage, etc) currently I'm downloading a 2gb game from steam (2.7mb/s download speed) and I'm in a Skype call with two others. Nothing else is being used. Somehow, the RAM is using 15.99gb of the total 16gb ram? I've got about 90% CPU idle, and there's no lag present...
Can anybody provide some insight as to why this is happening? 
Is there anyway I can prevent it....its kinda worrying considering how new the MBP is ^^
Thanks (:
Comments
Hopefully you'll be able to see that...? The memory pressure seems fine, and the RAM usage has dropped slightly since a few minutes ago.
Is there anything I should be worried about with it? Everything seems to be working fine, just wanted to make sure (:
It's just the file cache using over 10GB. This is just temporary storage, nothing to worry about.
Ah, okay, thanks ^^ That's really helpful, I'll stop worrying and let it do its thing haha (:
Sorry to bother you again, I just have one more question [: Do you have any idea what may be causing the file cache to be so high? I'm thinking being in a Skype call may have had something to do with it, as there were a lot of messages being sent back and forth, if so, is there any way to stop it from rising so high?
Finally, could it be effecting the hard-drive? It dropped from 475gb (everything had been downloaded by this point) down to less than 450gb? What would cause the sudden drop in memory? I wasn't downloading anything, saving any images, audio...it's really odd.
Thanks in advance (:
I would guess that they are treating it like the SSD cache in a Fusion drive. Every time you open a file, it keeps the file in memory even when it's closed so that it doesn't have to get it from a slower drive again. I doubt there's a way to limit it as it's not really a problem. The system will flush the file cache as soon as more RAM is needed. You aren't out of RAM, it's just that the space that used to be empty has something sitting in it until something else needs the space.
There have been tests done where people increase the RAM usage and the file cache shrinks and then Mavericks starts compressing inactive parts of RAM and they found that the whole system allowed as much as 24GB to be stored on a machine with 16GB of physical memory:
http://arstechnica.com/apple/2013/10/os-x-10-9/17/#compressed-memory
"Ask for more RAM in this situation and Mavericks goes after its own file cache while still holding the line on swap. Ask for way more RAM—gigabytes more—and the memory compression starts. Eventually, the use of swap is unavoidable. But just look at how far Mavericks can go before it finally resorts to swapping to disk."
50% more RAM for free essentially. It wouldn't be this much in every case but the Mac Pro's 64GB could stretch to as much as 96GB in a scenario with a lot of inactive memory.
That would happen if your swap was above 0. If you are on a laptop and it goes to sleep, it can write out a sleepimage that's as big as your RAM but you'd check using an app like Diskwave:
http://diskwave.barthe.ph
That will let you know what's using space on the drive and where.
Again, thank you, this is really helpful ^^ I'm downloading disk wave now, so that should hopeful help to sort out the hard drive, and I'm beginning to understand what you mean about the RAM. It seems as long as the memory pressure is low, the RAM can hold its own and sort itself out.
I think I can probably relax and let it do its thing now, apple are genius designers after all haha!! (:
Whenever you download the data will first pass through the File Cache on its way to your physical disk. So as the download proceeds the file cache will grow up to a max where all of your RAM is being used. When the download completes the data in the File Cache will remain until say Applications need more RAM and then the File Cache will reduce. It's all about the system making efficient use of your RAM capacity. It's a good design.