I was having some problems with the bandwidth between my Xbox360 and my Windows 7 Media Center. The connection is via a 87 foot long Cat5e cable that runs though my attic, so the stuttering and slow connection was a bit confusing. At first I thought something might have chewed through the cable, but figured I would test the bandwidth first.

Enter xJperf, a great Java front end for IPerf that comes with a pre-compiled Win32 IPerf binary.

It runs in a client/server mode, so with the use of a laptop (client) and my Windows 7 Desktop (server), I was able to see that my bandwidth was in fact terrible. A new realtek driver, some cable swapping, the disabling of Windows 7 Firewall, and a reboot yielded a 4x increase in bandwidth over the link. 

xJperf is now my second favorite network tool, behind the ever present Wireshark.