A few comments on OnTime web performance:

• The bulk of the performance issues with OnTime web is due to the javascript, HTML payload and network speeds.  The OnTime database is pretty well optimized and whether you have 50 or 500 issues won't make much of a difference.  For extremely large databases (10K+ records), there would be additional performance issues, but we're addressing those in V7.1.
• Things that affect the Javascript and HTML payload include the optional "Dashboard" and the "Multi-Edit" menu.  So if you're experiencing unacceptably slow performance, try turning off these features.  For the dashboard, you can click the "X" and to turn off the Multi-Edit menu, go to Tools menu -> User Options.
• It's unlikely that web server memory beyond 1GB will help increase performance much.  Although more memory on your SQL box can always help.
• If you're seeing other ASP.NET issues, etc. you definitely want to look into those problems.

Finally, we just announced OnTime V7.1 Beta which has a huge focus on Performance (although the bulk of the performance improvements are OnTime Windows and Remote Server focused, there are some goodies for web too).  You can read more about V7.1 beta and download it here:

http://community.axosoft.com/forums/11763/ShowThread.aspx#11763

Hope that helps.