I had FF800 a long time and now UFX, connected via Firewire.
Problem: system loses connection with the unit randomly. I have tried about everything to get rid of the problem:

- two different interfaces: FF800 and UFX
- two Firewire interfaces: ASUS P6T built-in 1394a and TI based expansion card
- four different cables
- all buffer sizes
- uninstalled and installed drivers (many times)
- tried all Firewire driver alternatives
- checked memory by memorytests
- disabled services
- reduced bandwidth
- checked DPC latency with DPC latency checker and LatencyMon. OK.
- tried to solve problem with Cakewalk Support.

System: Asus P6T mobo (latest Firmware), no OC, i7-950, 12 GB DDR3, Win7 Home Premium 64 bit EN (with all updates), Cakewalk SONAR X1d Expanded 64 bit, ASIO (44.1 kHz, all channels in use).

Connection may be losed anytime but the most obvious moments are
- arming a track in X1 when playback is stopped (when playback is on, problem has never happened!)
- opening a large project in X1
- saving Preferences (SONAR probably resets audio driver connection?)

Problem seems to happen always when trying to open connection with the audio driver. I have never seen connection getting lost during recording or playback.

Is there anything left to try, other than building a new PC from scratch?

-Panu