A bit hypothetical at the moment, but, will the HD621 pass upsampled 4K from an Oppo 103/105?

Maybe premature, but I wouldn't want to invest in a 4K capable screen and find that the HD621 is a bottleneck. I accept that the HDMI video feed could go straight to the display, but for elegance surely all HDMI feeds should go through the 'switchbox'? Particularly once Sky actually puts surround sound through the HDMI connection.

Roy Woods
Sony BDP-S370, G98DH, G68D, (FS: 562V), DSP5000C, DSP5000, M60, Pioneer PDP507