If it's not adequate for the tasks it shouldn't be promoted as such. The web page for the Macbook Air says it comes with Xcode, and runs a large external display. Perhaps I should have known better, but I tried to do my research. ;-)
I've experienced the exact same thing running a 24" LCD, firefox, and Entourage. Hardly an uncommon or extreme setup, but it's enough to throw the system off kilter. And when kernel_task goes into "cool this thing off NOW" mode, the system is unusable for 4-5 minutes.
The MBA is a beautiful monster.
I've heard that the revision B (128GB or 120GB hard disk) is more stable.
I think there's a disconnect here. Yes, it comes with Xcode. Yes, it's advertised as being able to run a large external display. But the question is: "can it do both of these things (in the case of Xcode, most likely building some complex project) simultaneously, and persist in so doing for an extended period of time?"
It appears the answer to that question is "no", and frankly I don't find that particularly surprising. I also don't think it really contradicts the marketing materials. Consider a different example: the MacBook Air comes with a wide variety of applications preinstalled, and this is an advertised feature of the laptop. But if I attempt to launch and use them all simultaneously, the system will become unusable very quickly as it runs out of RAM and has to start swapping. Does that mean Apple is falsely advertising its capabilities by touting the applications which come preinstalled?
There's a good chance that running anything on the external display is what's pushing it over the edge. If you look around, the most common complaint is that flash video (you know, non-HD youtube) is enough to kick the machine. In my case, it's Entourage.
or a £2k macbook pro.
I run my 22" external monitor, and a zillion other things and have never had speed issues.
The fact that the air can't seem to handle a second framebuffer and edit text at the same time is a little ridiculous.