I updated my network from SBS 2003 to Windows 2008 R2 a few months back, and am noticing some poor performance in showing network resources, and acknowledging changes. On a Windows 7 computer when I click on Network in Windows Explorer it takes several minutes to show the list, sometime it doesn't show at all. Same on my XP machines. It doesn't do this every time though, occasionally they come right up.
My latest test that really shows this is a simple HP printer. I loaded it on one of my Windows 2003 x64 servers. I loaded it's IP address and added the universal PCL driver and it prints fine from the server. I add it to my local Windows 7 system and it completes. When I try to print a test document, it shows offline, then after anywhere from 3 to 10 minutes, it will print the page. At that point it print okay. I changed the share name, reloaded the printer it takes the same 3 to 10 minutes. It also does this when I unplug the printer and reconnect it.
These problems may not be related, or I might not have enough information. Let me know what you need me to post for better info.