5 - 20 minuten
My early 2009 core2duo macbook pro felt like it was getting a bit long in the tooth lately, especially post-snow leopard. I started off adding 4GB of RAM, now 8GB, and a hybrid SSD/7200RPM 750GB drive to replace the 320GB 5400RPM conventional stocker. Even after these upgrades and various software tweaks in the interim, the computer still felt sluggish and off AC power battery life was very poor. According to iStat Pro the CPU die was @ ~58C on idle, running just a few basic apps and the OS (Mountain Lion). The fans hardly ever sat at idle speed, but were usually up near ~3k RPM. In forums, posters generally said this was normal operating temps for this machine and this OS. However, I decided to strip the notebook down anyways, as I had previously read that thermal paste has a life expectancy of only a few years before it dries out. While there was some dust in the fans, they had recently been cleaned when replacing other components. After applying the new paste (AS5) I am now almost always running below 50C, with idle near 41C. As I am typing this, with Mail, Itunes, Terminal, Preview, Vuze and Safari open, as well as a host of menubar apps (Better Touch Tool, iStat Pro, Sophos Antivirus, dropbox, etc.) the computer is running at 48C with both fans idling at 2000RPM. Even if this does not significantly improve the life expectancy of the processors, it certainly allows the fans to run more quietly, reducing battery drain off AC, and makes it more comfortable to use in the lap. I highly recommend this service.
The repair went fine. I took my time and it wound up taking about 2 hours total. This includes a second partial disassembly to re-insert the express card slot ribbon cable, which was just slightly underinserted, causing the card slot to be inoperative. The guide on iFixit was spot on. It really made the job easy with multiple pictures from multiple angles for almost every step. Don't get me wrong, this is still a job where a small screwup can render your expensive laptop a paperweight, but as long as you're careful and make sure you read the steps in full before you undertake the project you should be OK.
Do this now and wonder why you didn't do it earlier. I actually repasted my PS3 as a practice run, you get a ton of paste, enough to do 5-6 computers, so practice applying on easier to access CPU's (desktops?). Also, don't over apply! You only need a small amount (a grain of rice is often quoted as appropriate). One of the cited reasons we are redoing this is to apply it better than factory, and factory over applies typically, so don't make the same mistake!
Furthermore, do yourself a favor and buy a "spudger," if you don't have one, it makes those finicky connectors easier to remove and is nonconductive, worth the few dollars it costs.