Inactive memory is huge hit on performance

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ken_naylor wrote:

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Good answer, that will be very helpful to someone (I assume)

We're supposed to be helpful???

"I don't recall installing the 'developer tool' in order to do so. How would I go about doing that?"

Developer tools is in the App Store as "Xcode" it's free and that's how you get the command line tool purge

"Inactive Ram is memory that is available to any program that requests it, just as free Ram is," Yeah that's the thoeory; we all know that. Problem is in practice a fair number of us are seeing beach balls and a hight voulme of page outs when we have GBs of "Inactive" RAM i.e rather than using the Inactive RAM on the OS is choosing to use the HD for memory which is a huge hit on performance for those of us not on SSDs

What happens here is, after terminal->purge the inactive starts at once to grow and I think @ more than 4k a second, with all processes idle. typing now: firefox will cause the inactive to start eating more. I have Cubase connected to VE Pro and playback will start the blue to eat more memory.

It's going to be hard to start pointing fingers at 'third-party apps' I think. I bet I see this behavior using 'finder'. The issue is, I believe with 24 GB of physical memory I should not get a page out. Now, I don't get them until a certain amount of this blue section appears, ie., before I am in actual jeopardy vis a vis real memory. Typically the reason for this is 'inactive memory'. I took a nap today and inactive had grown to over 4GB in that time.

I assumed that this blue area would be distributed, ultimately, but I found this to be not_true. Ultimately I would have to quit everything and reboot, before learning of 'purge'.

'Free memory' does not work here. The 'purge' command works, so this is our answer. This is not a new to Mountain Lion thing, I'm on Snow Leopard.

I believe it might be against the rules on this site so i won't explain how to do it, but I have 16 GB of RAM on my mini and after some careful monitoring I eventually opted to simply disable paging. My main "memory hungry" application is VMWare so I have more control over its appetite and this has worked out quite well over the past year.

Another problem I was having was that a few programs seemed intent on swapping everything to disk and without a hybrid drive (on one machine) sometimes the OS would simply never be done swapping back to memory and I'd have to cold reboot it if I left it alone overnight.

Of course the Inactive memory still does its thing but it has never been a performance issue since, where performance is stellar no matter the distribution of memory; could it be that in some cases rather than free up Inactive RAM, or rather before doing so, the OS might encourage paging to disk if it can?

After more digging, I found BackBlaze the culprit in my case. Whenever it starts a backup, the inactive memory grows by 4k a second until it consumes all but 70 meg of memory. At this point, the machine is pretty much unusable.

While the purge command works for a while, as long as BB is active, the same thing happens. And yes, I've tried the fix on BB's site related to Spotlight.

For what I do, performance absolutely is affected when memory becomes tight beyond a point {and page outs}. This is where I noticed that the inactive was not available, I'm not concerned in the abstract.

Take your Mac to an Apple Store for hardware diagnosis.

Csound1, this seems to be a wide-spread problem. Doubtful we all are experiencing the same failure. If anything, it is a software issue, not hardware.

What hardware problem would create this? Do you feature that everyone that sees this has a hardware issue?
If that were true, Apple should quit making computers I think.

If it is a software issue reinstalling OSX would fix it, erase your drive and put a fresh operating system on it. Backup first

See my reply above, if it is not a hardware issue then this is the way to deal with it.

Ugh. This is the reason I left the Windows world. I had much rather stay with the occasional "purge" operation than to totally reload everything and chance all the things that could go wrong with that process.

If it is a software problem then a reinstall should fix it, do you want it fixed?