Windows Time (synchronization service) not good enough?

I have a PC that seems to have a horrible clock in it, and it's always running about 5 minutes slow. It's certainly possible that something on the box is messing with the date and time, I'm not sure. I do know that the Windows XP time sync that's built in just doesn't run frequently enough to fix the issue, so I went looking:

TimeSync is an NT service that keeps your system's clock in sync with an accurate network server.

[ TimeSync ]

I'm actually surprised I never found this one before. It's easy to install, works great, has tons of options, runs as a service, seems to be freeware, and seems to have correctly my clock issue for the short term.

I did disable the XP service that was syncing time, to ensure that this program was doing the work, which I think I'd recommend for anyone else.