I have had the same problem for 2 years already... thats why I'm constantly changing web-hosting providers... when I had 300 hosts/a day the hosters said the site scripts used 1150cpu (minutes of cpu time) per week, thats about 20 hours, a huge number. And the average scripts execution time was about 0.77 sec, almost a second, while different high-loaded forums scripts have not more than 0.2sec (those were the words of hosting support personnel). Then I had 1.7.4. version, and had an idea, that some code optimizations were made since the release of new versions... but now I've got 1.7.7, but the result is the same - even a whole day hasn't passed since my last "host move" and dns change, and I get another "critical server load" letter from support...
And every time I get the insistent proposals to optimize my scripts withing several days or to move to a dedicated server... a bit pricey...and early I guess with my 1K hosts/day now, not saying about those 300/day a year ago... and I constantly have to change hosting providers therefore, since I'm not such an adept in php or mysql to optimize the scripts
