Mac Mini Win7 Networking Slowdown Problems

[cncb]

I have the newest 2010 Mac Mini running Windows 7 x64 with the most recent Broadcom drivers and a Gigabit wired connection. Networking is fine for hours and then suddenly accessing networked drives becomes unbearably slow (takes 2 minutes to copy a 4MB folder that usually only takes a few seconds). I then have to reset the network card (disable and then re-enable in Control Panel) and it is fine for a few hours and then it suddenly happens again.

I did a bunch of troubleshooting with Broadcom support and they were no help. I am almost positive it is a Broadcom driver issue because I have an older Mac Mini in the same location with the same exact setup (except it has nVidia networking) and never had any of these network problems with it. I even wasted money on a new router to see if that was the problem but no luck.

This is driving me nuts - I would appreciate any help. It appears to affect only networked drives access and not internet browsing. Anyone have any ideas on settings I could try? I have already tried disabling IPv6 and "Checksum Offload" at the request of support. Thanks.