Why blame XP ? It could be as simple as that XP is better polished than linux(may be some experts can make linux work better but not necessary linux at its 'default' form).

I dual boot frequently between XP and linux(debian woody) and found that browsing the net under XP is in general faster and less problematic than under linux. I use Mozilla under both system(same version). I also experienced these timeout, or blank pages from time to time. Not a show stopper, usually just refreshing a few times would be fine. The configuration I used is orinoco silver on the notebook, through orinoco router/gateway through cable modem.