Many of the systems I've been in lately are HDSDI. What sucks in that I've been stuck using the crappy Gefen DVI to HDSDI Pro Scalers since that's what the company had before my arrival.

Using the x1900 I have no problems with the scalers. On the 8800s I had all kinds of issues until I wrote a custom EDID for them. The mini display port of the 4870 absolutely sucks with these scalers and I've lost connectivity intermittently.

The 8800 and 4870 will both do double TH2G boxes at 1024x768@25. The x1900 won't. Actually the 4870 handles the TH2G a little better I think.

I'm using Digital TH2G boxes and haven't yet tried the new Display port version. I'll get back to you when I do.