Using SISSoft's Sandra benchmark, ASRock's Q2900 / Intel Pentium J2900 measured about 10.5GB/s bandwidth figures. This is quite decent, and as evidenced below it places it the CPU in a bracket above AMD's A4-4000, but below the A10-7800.
In terms of day to day use, the fanless PC worked decently enough with applications like Excel, and Powerpoint. However, once I moved on to the Adobe Suite, the load times jumped over 30s depending on what kind of custom workload I had prepared for it.
Running PC Mark 8, the application side, which has integrated app loading and benchmarking in its suite. The results place Pentium J2900 (5%) over the similar Celeron J1900 processor, and clearly above (10%) AMD's Athlon 5350.
Intel has not been known for delivering good integrated performance, and that's in no way different here. I ran the benchmarks on a monitor with a 1680X1050 resolution, and across the board, I got some fairly bad results. All in all, if you plan to game, you won't do much on ASrock Q2900-ITX.
While at first, I decided to use an actual power-supply to power the system, once I saw the consumption figures, I realised the power-brick and integrated supply from AKASA's Crypto T1 is more than enough. In Idle, Q2900-ITX and J2900 eat up only 30W, and in full-load using Prime 95, the power needed to fuel the machine is only 39Watt, which is more than decent.