• Could you run SQL Profiler against your database and see which queries are taking the longest to execute? From that you could see if you have

    a) Poor indexing on your tables

    b) Poorly written application software that does things like selecting * from an entire table just to get a record or two

    c) Lots of blocking - eg holding open a transaction whilst a user responds to a yes/no question on screen

    d) Table scans vs index seeks

    Poor performance is not always solvable by throwing more resources at your server. Often it's due to poor application design. Could you run profiler as suggested and perhaps post some of the queries here along with sample data and table structures? Before posting please read http://www.sqlservercentral.com/articles/Best+Practices/61537/

    After ensuring your problems are not any of the above then we should consider putting transaction logs onto different drives from your database files, etc. There's no point in trying to put a V8 engine in a car with inadequate steering and a poor gearbox (make up your own analogy to suit 😀 )