I noticed the HDMI output of 5770 is very different from my old 4850:
HD4850: YCrCb 4:4:4 pixel format output from 4850 is perfect, I get both WTW and BTB, the colour is accurate and the grey dump looks very smooth. I've tested both PowerDVD(pdvd default DXVA decoder) and MPC-HC(ffdshow as video decoder) with overlay renderer and both worked fine. RGB 4:4:4 produces accurate colour and smooth transition B/W but I didn't get WTW and BTB information.
HD5770: YCrCb 4:4:4 also gives WTW and BTB in overlay just as 4850, but only in PowerDVD. I've checked the grey dump, and it looked horrible: the transition isn't smooth at all. Besides, the colour is way off and I think something must be wrong in the video pipeline. Overlay in MPC didn't give me BTB and WTW anymore, and the output was compressed to something around 50-220 (grey black issue). I then switched to RGB 4:4:4 and tried EVR renderer, everything works fine again except that I didn't get WTW and BTB anymore.
All colour and contrast settings in CCC is disabled and my display panny AE3000 comes with a waveform monitor for RGB colours, so I think the result of my test is reliable. I've also double checked with my DVE blu-ray disk.
Another problem I noticed with powerplay is that when the TV is turned on, it raises freq to the 500/1375, and it never goes back to 157/300 even when TV is turned off later. I have found a work around for this issue: change profiles.xml and set lowest freq to be 157/300, and that will make sure when you have TV connected powerplay won't raise the freq.