CPU Usage of Unused But Open Apps

steiney

macrumors 6502
Original poster
Nov 6, 2009
479
29
Hello All!

I have a question regarding the CPU usage on my MBP and figured this would be the best place to ask.

I've noticed that even when a large, CPU intensive app such as Photoshop is open, as long I don't have any images open that I'm working on, the CPU usage of the app is minimal (around 1-2%). By this logic, would it make sense that I could keep open all or most of the apps I use that take forever to open so that they would be ready to go when I need them, and that it would not tax the CPU too much and slow down performance? If I kept 10 apps like that open, I would be only using 10-20% of the CPU, which seems like it would leave enough over to have a properly functioning computer. The computer I am using is a 2.33 GHz Core 2 Duo with 4 GB of RAM. Now that I'm thinking about it, having 10 large apps open my be too much for the RAM. I don't know enough about RAM to know if that would be too much for it. I can't wait until I'm ready for my next Mac. I've been on the same MBP for over four years now, and I'm wanting to make this computer last for another two years, approximately.

Well, I'm happy to hear any asnwers or opinions.

Thanks,

steiney
 

yg17

macrumors G5
Aug 1, 2004
14,910
2,480
St. Louis, MO
Hello All!

I have a question regarding the CPU usage on my MBP and figured this would be the best place to ask.

I've noticed that even when a large, CPU intensive app such as Photoshop is open, as long I don't have any images open that I'm working on, the CPU usage of the app is minimal (around 1-2%). By this logic, would it make sense that I could keep open all or most of the apps I use that take forever to open so that they would be ready to go when I need them, and that it would not tax the CPU too much and slow down performance? If I kept 10 apps like that open, I would be only using 10-20% of the CPU, which seems like it would leave enough over to have a properly functioning computer. The computer I am using is a 2.33 GHz Core 2 Duo with 4 GB of RAM. Now that I'm thinking about it, having 10 large apps open my be too much for the RAM. I don't know enough about RAM to know if that would be too much for it. I can't wait until I'm ready for my next Mac. I've been on the same MBP for over four years now, and I'm wanting to make this computer last for another two years, approximately.

Well, I'm happy to hear any asnwers or opinions.

Thanks,

steiney
You pretty much nailed it. RAM is what's limiting you. The open apps might not be using any CPU, but they're all using memory, and once you've used up all your physical RAM, your computer has to start using virtual memory on your hard drive which is much slower.
 

steiney

macrumors 6502
Original poster
Nov 6, 2009
479
29
Thanks! Is the virtual RAM too slow to work well as a substitute for my regular RAM? Does the OS have any sort of way of prioritizing what processes uses what RAM?
 

MacNut

macrumors Core
Jan 4, 2002
21,797
8,005
CT
Thanks! Is the virtual RAM too slow to work well as a substitute for my regular RAM? Does the OS have any sort of way of prioritizing what processes uses what RAM?
Virtual RAM is just the hard drive doing double duty. That is why it is slower than physical RAM.

The only way to prioritize the ram is for the program to use it efficiently. The computer just gives the program what it needs.
 

iJohnHenry

macrumors P6
Mar 22, 2008
16,532
16
On tenterhooks
Virtual RAM is just the hard drive doing double duty. That is why it is slower than physical RAM.

The only way to prioritize the ram is for the program to use it efficiently. The computer just gives the program what it needs.
Or get an SSD, and worry less about read/write times. :)
 

steiney

macrumors 6502
Original poster
Nov 6, 2009
479
29
Yes sir, my next Mac will absolutely have an SSD. I can't wait. And either 16 or 32 GB of RAM. Hopefully 32 GB will be at the current 16 GB price level in a couple years.