Does anyone know if my PSU is suitable for an ABIT AV8 3rd Eye mobo with AMD/64 socket-939?

Info on PSU: Q-Technology ENS-0240QT 400 Watt
+3.3 V 30A
+5 V 25A
Max 200W on the above 2 voltages

+12 V1 15A
+12 V2 16A
Max 216W on the above 2 voltages

-5 V 1A
-12 V 1A
+5 V StandBy 2A

There is also a 6-pin flat cable-connector with Red/Orange/Orange/Black/Black/Black colours. Does anyone know what this might be for?

if it actually meets it's ratings it'll be fine. that single inline connector sounds like the one for the old Pentium motherboards, Pre-ATX power connector.

PC Repair and Maintenance: In-depth Look at Power Supply