Vista Beta 2 Remote Desktop Problem

I installed Beta 2 on my main home workstation 3 weeks ago. I can
connect to it from my XP Pro laptop using RDP on the home LAN with no
problems. When I connect to it from work (through a T1 line to Charter
broadband) it connects but has problems. The screen refreshes very
slowly. Actually, it works fine for a few seconds then freezes for about
30 seconds then repeats. The mouse pointer still moves around but
doesn't highlight anything. It acts like a video buffer problem. I tried
tweaking the connection down to 28.0 modem speed and using lower screen
resolutions but nothing changes. When I first installed Vista it worked
fine but something has changed. I checked the event logs on both
machines and didn't see anything to explain it. Task manager shows very
low CPU usage when connected.

The server side (workstation) is a 6 month old box with an AMD 4200+
with 2 GB of dual channel memory on an Asus A8N Sli Premium MB. Video is
a single eVga 7800 GT with 256 MB of memory. The server is not part of a
domain. The client side is a Pentium 1.6 Mhz with 512 MB of ram. Video
is an ATI All in Wonder 8500. The client is on a domain.

Any ideas? I checked Goggle but there isn't much with Vista and remote
desktop.

Thanks,
Dave