Android Guys reports that a HTC media relations employee commented on the 30FPS issue that Evo users have been reporting.  This issue mainly effects gaming and other UI elements on the device. The employee states that the limit is imposed by software due to the processing requirements of the HDMI port.

Considering how much I use the HDMI port (none), I’m kind of surprised that HTC didn’t provide an option to disable the port or use a cable detection algorithm to speed up graphics when HDMI output isn’t needed.

As an upside to the story, a few developers over at the XDA Developers Evo Forums have been working on a fix for this issue.

Source Story: Android Guys