I've got a late 2011 macbook pro 13" with 4gb ram, 500gb mechanical hard drive, running mavericks. I'm trying to figure out what upgrade is needed, or if it is even possible to upgrade, to speed things up a bit. Application load time itself doesn't bother me much, my concern is more with sluggish performance, which makes me think upgrading to 8gb ram will do the trick. I don't use a lot of heavy applications. At any given moment, I usually have music running through iTunes, pandora, or spotify, web browser open with a few tabs, mail, messages, tweet deck, and evernote open. With this, I'll often get sluggish performance where pandora might completely stop working as I'm opening another new tab, when i click the address bar to start typing there is a 2-3 second delay before it will register that i'm typing, etc. Anyways, I've been watching activity monitor and the memory pressure has always been in green. Even when put under high stress (opening about every application in my dock and opening 15ish tabs in safari), things come to a halt, but pressure stays green and swap stays at 0. Any thoughts would be appreciated. Personally I didn't think the sluggish performance was HDD related as it says it isn't using any swap and application load time isn't a huge deal for me. I was thinking RAM could be it, but again, it stays in the green and never uses any swap. If it's helpful hers some other status when pushed it beyond normal use to test: physical memory: 4GB memory used: 3.99GB Virtual memory: 5.91GB Swap used: 0 bytes App memory: 1.93GB File Cache: 204.3Mb Wired memory: 1, 016.7 Compressed 891.9MB Any help is appreciated. I'm hoping to get this computer to last another couple years and I'd also like to upgrade to El Capitan, however, when I upgraded to yosemite the sluggish performance intensified a ton, so I'm a bit afraid to do so. Thanks!