I got a device yesterday (courtesy of GPD, thanks guys). And I want to comment several aspects that I have noticed.
- Device is pretty similar to q89. Performance in emulators is pretty much the same, except for a couple of things. Some PSP games run better and Broglia's emus can be used with hq2x filter without issues, something that was not possible with RK3188.
- Performance in GPU is very good, a bit worse than my phone but fast enough to run games without issues.
Now, in terms of firmwares, I want to clear some points. I have tested 1.07 firmware, and although kernel is set up to 1,8 ghz, the true speed as I thought is 1,6 ghz. That is normal in RK3288, so no a big deal. However, that changes in firmware 1.1.2, which was the one installed in my device. In 1.1.2 CPU max speed is marked as 1,6 ghz, but indeed max speed is 1,416, so device is underclocked. My guess is that GPD did that to avoid some heat and probably because the board have some issues running at max voltage during some time, probably due to the lack a good heatsink (or no heatsink at all).
Apart from that, firmware is very stable and no problems so far. Even at 1,416 ghz everything I tried in terms of emulation runs ok, and honestly even at 1,8 ghz wouldn't make a big difference except for a better antutu benchmarks from my experience with my RK3288 tv box.
But in the end, my point is that there is no single firmware in which the system runs at "true" 1,8 ghz speed, not even the 1.07 one.