Windows 7 clients attached to SBS 2003 slow bootup/login/browsing; XP clients OK

I'm assisting a client that is running a fully patched SBS 2003. 5 computers on domain; 2 are XP, 3 are windows 7 professional 32-bit.

All 3 Win7 PCs are new HP 6200 SFF, fully patched.

The Windows 7 PCs take a long time to boot up.. it's 3 minutes before the login screen comes up, and after authentication its 2 more minutes before the desktop is up. Once logged on, local network browsing is very slow as well (30 seconds to open a small, 1 page PDF for example, from a local network resource). Network is 100MB, so no gigabit, but ping/throughput to the outside world is fine. Files download quickly, external sites come up instantly, the problem is only when booting up, loading the profile, and browsing intranet.

Making this more interesting is the fact that if the PCs are removed from the domain but still physically attached to network, it boots up instantly, logs in instantly, and browswing local network resources (after authenticating to them of course) is instantaneous.

There may be one more more causes, I accept that... I've combed the event log and see some group policy (errors 1501/1502) events that may indicate delay, but they don't show up every time. Also, that wouldn't explain the slow browsing of network resources.

I've done some research (read: googling) and not finding any specific incompatibilities between SBS 2003 and Win7. Could this be a kerberos issue, and if so, how would they resolve it? I believe I've demonstrated it's not a hardware issue since performance is fine if they are off domain, so it seems like it's a delay processing something on startup and then delays while accessing resources on the network that are relying on cached credentials.

Any input is welcome.

Resolved issue, nevermind, OK to close/delete