Well, it's a 1366x768 fixed pixel display, so they'd all be visible. The question is whether the set's circuitry is designed to make use of that slight extra resolution at any step before final display.

HD, being digital, doesn't need to store its extra information in unused resolution like NTSC.

Resolution conversion really shouldn't be difficult - think of playing a movie back in Media Player on a PC... you can make the window any size from a thumbnail up to full screen and the CPU usage doesn't change.