[vanekl]

The raw performance between Sql Svr and Mysql are pretty much a wash. If you primarily base your decision on this, you are overlooking quite a few more important issues. Hardware (Raid level, Ram, CPU), DB driver, programming language, and caching are all more important issues.

Non-speed issues: 1. Sql Svr 2000 had locking problems such that many transactions deadlock and automatically get rolled back. This was due to page locking. I think MS fixed this in 2005 with record-level locking. 2. Sql Svr has very nice stored procedure support. This can be extremely useful. If you think you may need this capability, then Sql Svr is the better choice.

If you do decide to go with Sql Svr, you will probably end up having to get a copy of VS 2008 and do some C# programming. It's almost impossible to maintain Sql Svr w/o it, unless you want to maintain the db by hand every day.

It doesn't sound like you have much db experience. Get a couple of experienced db admins in to talk with you before you make any big decisions, even if it's just a two hour consult.