I had a really hard time with them when trying to troubleshoot issues with the 2895 board and the Highpoint Rocketraid 2224. Highpoint would email me replies within the hour and returned a few phone calls. Emails and phone calls to Tyan went unanswered for about 10 days at which point I got an extremely unhelpful canned email response (install the latest firmware and try again). I won't be buying any additional Tyan boards and sent all but 2 of that batch back (I'd deployed 2 as desktops while waiting for answers from Tyan and was too lazy to swap them out).
Back in the 1990-1998 era, I used lots and lots of Tyan tomcat boards and was happy with support. So perhaps they are dropping (or have dropped) the ball.
:(
Where else can one go for solid, high I/O whitebox motherboards that support AMD processors?