Just to make sure we understand the question...
You have a PC with an HDMI output, and are connecting your PC to an RCA brand Roku TV device via HDMI?
If so, what is the resolution of the PC? If you're running Windows 10, on the computer go to Settings > System > Display, and look at the Display Resolution setting on the computer.
Roku Community Streaming Expert
Note: I am not a Roku employee.
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