One of the points you have to check is: does SQL server use both processors (if present) in the server? There is a setting for that. Do not ask me which setting it is...
It may be that some database tuning or optimizations are required. Also software can be the problem, but is not that likely to be. If so, then other Baan users would complain also and very bad performance will result in better performing software. It is however possible that changes to enhance the speed on a Level II database driver (such as Oracle) will decrease the speed on a Level I database (such as SQL).
You can run the session with various loggings (TT_SQL_TRACE=0240 to start with) to see where the performance gets lost.
Also the use of sessions (selections given) can cause bad performance: usually the form of a session is built up using index 1 on the main table. So if the first (key)fields are not used, and the last (key) fields are used, then the session should actually pick another index instead (having these last fields filled on the form as first fields in the index to reduce dataload by the database driver), but this normally does not happen (needs a lot of ugly programming to have it working for all possible choices). So try to run with tight selections as much as possible.
Also read Luke 24:4-8