Radeon 7750 can't wake up from sleep in Mavericks

[grassmudhorse]

Hi, I recently replaced the noisy GTS450 with a Sapphire 7750. Everything works out of box in Mavericks including dual display.

 

Now I found out that my machine won't wake up from sleep. I would get an error of:

kernel[0]: AMDFramebufferSI::setPowerState(0xa8ae1b5eb4a90515, 0 -> 2) timed out after 45269 ms

 

I am not sure if anyone else has the same problem? I am using MacPro 5,1 as the system and my AGPM shows loaded but unknown card. Anyone has the same problem? Any advices?