I have a 2011 mba 11" with 2gb ram and it was running fine but it seems kinda sluggish now... I mean even an e-book on preview and 2-3 firefox tabs seems a lot for it to work fast. Might it be that it's connected to a 1080p external display? But it wasn't like that from the start. It's very slow when I'm doing things on the external display, either browsing or reading. Also, I never have more than 100mb free ram, even though I have like 700mb inactive. I read that inactive is as good as free, but is that really true? Otherwise why would it be slow if I have so much free ram? Is it the GPU's problem?