Difference Between Inactive and Free RAM in Activity Monitor

[JasonGough]

I'm hoping to buy another gig of RAM soon, but not sure if i need it. I have 1 Gig already.

Checking activity monitor when i'm raping my mac with ProTools running a big mix still shows it has some free RAM.

more interestingly, there is usualy a large portion of 'Inactive RAM', and i was wondering what this is? Is it stuff that is is RAM that is not currently being used by a program? if so, why not free it up for the current program?

 

[Benjamin]

inactive ram is ram that is allocated to applications but not in current use, just allocated for future use. That ram is also free to be reallocated by OS X will but if you aren't stressing every application there is no need for OS X to do this. OS X has a good memory management system you rarely need to worry about it, imo.

 

[cemorris]

I think the most important thing to look at is the page outs. If you have a lot of those, then I would say you need more memory. Page Outs = Swap space access = disk access = slow

 

[Spectrum]

I'm a bit late to this discussion. But I have a relevant query.

I'm on a 15PB w/2GB RAM, I've just been doing a lot of file copying across a network and now I am left with only 80MB of Free RAM left.

Only 280 is Active, 140MB wired (what does that mean?)

and a whopping 1.52GB Inactive!

VM is up at 6.7GB, (but this is pretty normal from my experience on this computer)

61070/0 : Page ins/outs.

The Free memory is slowly counting down. Is this because I am sharing an mp3 to my iMac?

What happens if/when the Free memory hits the wall? - it looks kind of like a time bomb at the moment...

I think the most important thing to look at is the page outs. If you have a lot of those, then I would say you need more memory. Page Outs = Swap space access = disk access = slow

 

[mad jew]

Has everyone read this? It's brief, but still a good guide.

 

[Spectrum]

Thanks - I really should have searched Apple first. Ho hum.

Anyway, memory dwindled to about 25MB, then it must have paged or something, because now Page in/outs is 77128/1322.

I'm afraid I don't really understand the paging process. Is an "in" a write IN to disk, or a copy IN to memory, etc.

Now: I have very little running, and on launching Photoshop, the ins went up some more (free memory is back down to 28MB).

How Do I get the OS to discard all the stuff it is holding in the inactive memory - or doesn't it matter?

Has everyone read this? It's brief, but still a good guide.

 

[mad jew]

Don't worry about the memory whatsoever. If things start slowing down and you're noticing more and more page ins/outs, then either buy new RAM or do a quick restart to clear it up.

It's a complicated system that is difficult to understand but the long-and-the-short of it is that it works.

 

[crazzyeddie]

Unless your pageouts are getting large (20,000+) don't worry about your RAM, unless you really see slowdowns.

 

[NicP]

I'm on a mini with 512mb ram. Uptime says 16 hours but i havent been using it the whole 16 hours. Page ins/outs are 71673/30230.

I assume adding more ram is a good idea? I'd see a significant difference right?

 

[mad jew]

Well NicP, whether you notice a difference depends on what you use the computer for at the moment. RAM will only speed things up by cutting down on the slow task of reading and writing to the hard drive by storing data in itself. The more RAM you have, the more data you can store inside it and the fast that data can be accessed. Upgrading a mini's RAM means that you lose whatever RAM you currently have in there. So, you'll be paying for a 1GB chip and will then e able to use 1GB in total. For general usage, I think most people are fine with 512MB and considering the cost of getting that 1GB stick, I'd think carefully before purchasing anything.

What sort of stuff do you use the Mac for?

 

[NicP]

Well NicP, whether you notice a difference depends on what you use the computer for at the moment. RAM will only speed things up by cutting down on the slow task of reading and writing to the hard drive by storing data in itself. The more RAM you have, the more data you can store inside it and the fast that data can be accessed. Upgrading a mini's RAM means that you lose whatever RAM you currently have in there. So, you'll be paying for a 1GB chip and will then e able to use 1GB in total. For general usage, I think most people are fine with 512MB and considering the cost of getting that 1GB stick, I'd think carefully before purchasing anything.

What sort of stuff do you use the Mac for?

Its not my mac, i'm looking at buying it from a friend. But if i was to buy it i'd be using it for music production (Ableton Live), along with the usual email, photos, irc, msn, word, excel etc. etc. (i have a capable linux box but the only thing it doesn't run is Ableton Live )

I'd love to buy a powerbook, but perhaps a mini could suffice until Intel powerbooks are available

 

[mad jew]

For music production (and considering the slow-as-molasses hard drive speed on minis) I'd stump up for the 1GB chip.

Of course, you don't have to do it straight away. Run it with 512MB for a while and see how it goes.

 

[breeves002]

I think I beat you all with inactive ram...

I'm running an 8 core mac pro right now (2x4core 3.2ghz/6gb ddr2-800/2.5tb)

When I use handbrake 64bit on snowleopard, (which usually can max out all 8 cores), I get a whopping 3.24gb of inactive RAM! Only 132mb free. Handbrake of course has it allocated. If I closed final cut pro, I would get back even more RAM. Don't worry about your inactive ram, it will be reallocated if needed somewhere else. You know you need more ram if you are using 80% or more at startup with only your basic applications open. I recommend at least 2gb, but some people will need even more. The nice thing about having a mac is that even with low amounts of ram, it can still function pretty well. My other mac pro is from the same era, just slightly slower processors, and only 2gb of ram. I have no problems running final cut, etc. I would buy more, but the ram is SOOOO expensive! Try buying DDR2 800 FB ECC sometime...