I'm experiencing some very slow load times on my network,

I'm experiencing some very slow load times on my network, so started running some tests to see if some of my plugins are causing issues.
After shutting off several plugins that I could probably live without, I've gained a little time, but still taking too long.
With Autoblog activated it's taking about 5-7 more seconds to load than without. Obviously, that's quite a bit. I've tried with and without about 4 or 5 times each.
Tests with 15-20 seconds
Tests without 8-12 seconds
I really need to be able to load blogs via RSS somehow. Any ideas?
Thanks,
Joe