I found Dreamhost to be slow as well. I moved from the cheap option to there 'Private Server' option, which allows you to adjust the RAM and processor you're alloted. Didn't help a bit. I personally think they have overloaded MySQL servers, so throwing more RAM or processor at the problem didn't help. I've moved my main blog (
http://itsvista.com) to Media Temple on there Grid system. It's cheaper than I was paying for the Private Server at Dreamhost. So far, I've had a few slow times, but overall it seems faster. I may still step up to their Virtual Server, which should resolve any issues since you're file server and SQL server aren't shared with anyone. Costs a bit more (starts at $50 per month), but may be what I need to be completely satisfied.