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My iMac (2010, i3, 3.06 GHz, 4GB RAM) has been getting a little slower. My research shows memory can cause a slow performance, so I looked and most of the time, my RAM is allocated like this:

Here's my memory usage.

Would resetting my Mac to factory settings increase performance/speed it up?

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How are you measuring the slowdown? –  Mark Feb 1 '13 at 14:19
    
Also - how typical is this scenario? You have a healthy amount of page in and page out, but that also can be shown in a stable, well balanced system that's performing at it's peak capacity and full speed. –  bmike Feb 1 '13 at 14:24
    
@bmike actually their page outs are quite high, indicating disk thrashing. They need more RAM. –  cksum Feb 1 '13 at 16:13
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@cksum Do we know over how many days 16 GB was paged out? I'd not worry if it doesn't reboot regularly since it's the paging rate that defines thrashing, not some total amount since boot in most cases. We would know if the OP posts the Disk Activity snapshot as well as the System Memory one. –  bmike Feb 1 '13 at 16:19
    
@bmike, you don't have to know. It's a percentage. Optimal cases should see no more than 1% of page-ins. So in this case, it should be about 2GB, not 16. The 4GB swap is telling too. It could be a single case that brought up the numbers but that's really unlikely. 4GB is just not enough these days, even if all you do is surf the web. –  cksum Feb 1 '13 at 16:25
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I would say, that your RAM usage is not the issue, but you would need to edit in some more measurements about what is slow (or make the detailed measurements in the first place) and look at perhaps network latency (web pages take a while to paint), network bandwidth (iTunes movies take hours to download instead of minutes), or CPU perhaps.

In the RAM snapshot, the system looks to be used lightly, due to a small amount of inactive RAM and the large amount of free memory. Over time, if your programs need more than half the RAM for active and wired, you would see a speed up when switching between seldom used apps if you doubled your RAM so that rather than releasing memory, the system would build up a larger cache of "inactive" memory, but that's just speculation.

Why not pick one or two things that seem slow to you and make 10 measurements on how long they take. At that point you can ask a more pointed question or perform the restore and re-test the speed to see if your change made any difference.

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In my experience, it's often virtual memory that slows things down, especially if you have a Mac with a hard disk. You're using 4.8 GB of swap files, which is a fair amount, and if you have an app that is swapping a lot, that prevents other apps from accessing the disk at the same time. My Mac mini, with 16 GB RAM, and an uptime of over 5 days, currently has 0 swap files. So adding RAM will help with swapping, but also trying to find which apps are the culprits may help as well. And if you restart from time to time, you'll find that speeds things up, as the swap files get deleted.

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But there is >1G of free memory that will be used before needing to swap and no page ins or outs so the OP is not limited by swap. Swap files are allocated when you load anything even of all in memory. –  Mark Feb 1 '13 at 14:19
    
Swapping doesn't only depend on free memory. Apps may swap while there's still free memory, or they may swap and then other apps release memory, so there is more free memory again. I wouldn't use any recent Mac for serious work with only 4 GB RAM. –  Kirk McElhearn Feb 1 '13 at 14:20
    
the page in/outs show this is not happening –  Mark Feb 1 '13 at 14:21
    
I also feel swap would generally nor be a problem with that level inactive memory and that much free RAM. A better test for swap is running vm_stat and perhaps fs_usage and seeing that IO are being slowed at the same time as swap activity taking place. –  bmike Feb 1 '13 at 14:21
    
You are however, very correct in pointing out how much RAM was swapped out (and even a decent amount of RAM swapped back in). It's much larger than I normally see, but as long as that swap is gradual and not time sensitive, it could be a feature to keep the system fast, rather than the cause of slowness. +1 for addressing that even if I don't see a smoking gun (yet). –  bmike Feb 1 '13 at 14:27
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