I am trying to find some infromation to compare these two database server. The reason why I want to get some info sue to personal experience with a forum. I believe it's using MySQL. For years, the performance of that forum is wrost than 3 years. It has fairly large number of posts.
So I wonder MySQL's performance when handle more than 700MB data and hopefully someone could help me.
At 700MB you should find both MySQL and MSSQL both pretty good - I suspect you could benefit from archiving old posts though - have you tried this? It may be a cheap and easy solutions for you!
I do have a database around that size running in MySQL and have no problems at all. It all depends on the server hardware, RAM, disk speed and free space, load. In the database itself, indexing is of the utmost importance. Rebuilding indexes may help, but probably you can also benefit from some customized indexing.
I would start by rebuilding indexes and see if that helps.