I use
Cyberwurx because they don't have problems like these. I used to deal with hosts that told me Wordpress was my problem and that it was a resource hog. Then I found out it was how their shitty servers were set up.
Before Cyberwurx my network of blogs with about 25K hits a day (at the time) ran my 4 core server to 7.xx load which means almost half of the requests were being rejected by my overloaded server. I bounced from host to host looking for relief, but couldn't find it. Then I was told by another WP junkie about Cyberwurx and their own blend of Linux. It brought my server load to 0.14! Which means I was using about 15% of one core equivalent.
Guess what happens when you have a kickass server? You get more surfers!