Stop mt-comments.cgi to save memory

I can not publish new post in this blog. So many 500 error when I click publish, some times when I click signin.
The 500 internal error is because my blog, MovableType ate a lot of memory when it running. The Dreamhost is monitoring the resource user is using. It will kill the thread when it over the limit. Actually they don’t tell you the limit of it. They just tell you, it is time to upgrade to their VPS.
I connected the server through ssh. Run top command to see which one is more popular.
Yes, I found it. More than one mt-comments.cgi stay on the list.
To temporary solve the problem, I rename the mt-comments.cgi to other name. Then sign in the backend of MoableType.
Click Settings, Feedback, Uncheck the check box after Accept Comments.
Then, republish the whole site.


It is not a good solution. I am looking for a long term way.
1) Maybe move the site to a VPS, not Dreamhost VPS, but others.
2) Change blog platform from MovableType to WordPress.
There are so many users of MovableType have already moved to WP. I can do it too.
VPS has better performance then shared hosting. If want a better SERPS, VPS is the next step.
Do I choose one of above, or combine two to improve my Blog?
Give me your idea by comment it.