I have recently been fighting with OS X Lion regarding performance on my older, early 2008, black, 13 inch MacBook (2.4GHz Intel Core 2 Duo, 4G RAM upgraded from the stock 2G, and a 500G WD Scorpio Black 7200 RPM drive upgraded from the stock 256G 5400 RPM drive.). The only change was the upgrade to Lion. Here is what I have observed:
- Using Menu Meters and the system's Activity Monitor, I have observed performance, and computer behaviour correlated with application usage. Typically I run quite a few applications constantly: Mail, iCal, Address Book, Adium, Evernote, Synergy, Skype, Fastscripts, SizeUp, Time Machine, OmniFocus, Dreamweaver or Photoshop, iTunes and BBEdit. I should also note that I typically run a 25" Asus monitor as well as the MacBook's internal monitor.
- After upgrading to Lion my computer started to have a number of performance issues. Most annoying was a frequent, several second pause. The entire computer would appear to freeze for a number of seconds. Not an hesitation, but a full-blown pause.
- When I had the large monitor disconnected, and was just running the internal monitor, these pauses were almost non-existent.
- The fans would come on much more frequently than usual. Prior to Lion, my fans would come come on only when Time Machine ran to sync with my constantly connected (by Firewire) 1TB WD Green in a NexStar single drive dock.
- I did a lot of research on the Web, and found a number of interesting, related, and useful links. Some of the topics which were useful included Apple's 'Mingler' process, Safari's 'Safari Web Content' process, OS X swap file usage, older Macs unofficial RAM capacities, onboard vs dedicated video RAM, the 'purge' command, and OS X performance issues in general.
- Using menumeters I observed that my system pauses were related to physical RAM usage. When the RAM meter hit the 'full' mark, my system paused.
- Using menumeteres I observed that my fans came on when my CPU usage climbed. This CPU usage did not cause a pause or hesitation. Just the fans came on.