I noticed that my web app, which makes anywhere from one to many MySQL connections per page was running slowly on my new Windows 7 RC laptop. I used dotTrace to compare the page execution to that of my desktop (which runs the app very quickly) and noticed that it was all the MySQL connections that were taking 10x to 100x as long to execute on the laptop.

After a bunch of troubleshooting I finally determined what was causing the performance problem. It was Nod32 4.0. I couldn't just disable Nod32, though. I had to completely uninstall it to cure the MySQL ODBC slowdown!

With Nod32 4.0 installed, some pages were taking 13 seconds to execute.
Without Nod32 4.0 installed, those same pages were taking less than a second to execute.

I observed this behavior on two systems:

1. Dell Inspiron E1705 w/ Windows 7 RC x86
   
2. Dell Studio 16 XPS w/ Windows 7 RC x64 (happened with both 64-bit and 32-bit ODBC drivers, and with both 3.51 and 5.1 versions of each)

Both systems have Windows 7 so this could be a problem only for Windows 7 users with Nod32 4.0. Maybe it's fine with Vista or some other anti-virus application. I hope this helps someone because it took me FOREVER to figure out it was Nod! I sent their support an email explaining all this. Hopefully they will write back with some info. Aside from this, which is a DEALBREAKER, I love Nod32 :(