I have a Team City Server, and TFS 2010 with de TFS DB in other server.
Both Are Virtual Machines over a ESX Server (monster server for virtualization)
The thing is, from VS 2010, check-in, check out are pretty fast
But From team City, the checking for changes process of the Build configurate take around 15 minutes or more,
The size of the Collection Database its 400 MB (its not than big) el sise of the all the code of the project about 16 mb including packages
Everything runs over LAN configuration
the Team city server had installed VS team explorer 2010 and net framework and SDK
Depending on your TeamCity version take a look at this issue http://youtrack.jetbrains.com/issue/TW-13046
It solved the issue for us