I've also noticed the slowness. I googled a bit online and I found this one comment:
If you're too lazy to click the link, here is the comment itself:
"Your slow-downs may not only be due to WordPress, but that DreamHost has quite substantial performance problems with their MySQL servers at the moment. Having just bought an account with them, before switching I’ve been benchmarking their database performance (open a connection, then perform 4 different queries on a datbase table of ~9MB):
my old host (who suffer from awful support and bad management of servers) using the identical test:
So far, there is a massive difference; in initiating a connection I get a mean latency of some 125ms+-1456ms standard deviation (n=2021 — my old host is about 4.5ms), it is as if the server is across the Atlantic (125ms is the hop from LA to London!), and then queries are about 3-10x slower. These values hold on at least two of the DreamHost MySQL servers.
I am collating statistics over a few days and will submit it as a report to them, I’ve heard they are good about responding to such input positively. Anyway I suspect the “slowdown” could be drastically reduced once DreamHost get a handle on their poor MySQL performance. "
... and I went to both of his mysql query benchmarking scripts. And yes, he was right, mysql does seem to be terribly slow on dreamhost. The four queries range from 80 to 140 milliseconds on DreamHost, but 1 to 14 milliseconds for the commenter's previous hosting provider.
This is pretty ridiculous. I hope that this gets fixed right away before I start to change my mind about this hosting... The lag on my wordpress blog is starting to get quite annoying.