Here's some specs I found on the Anchor bay ABT2010 chip that the 2310 uses:
Anchor Bay » ABT2010 » Advanced Video Processor
It contains the onimous phrase "3 frame video processing delay", however that's under the section about deinterlacing, and we seem to be experiencing delay even when converting progressive signals.
Also on that page is a reference to the "ABT2010 video delay calculator spreadsheet (.xls)", which is only available under NDA apparently
Presumably that would tell you what delay you can expect under different scaling/conversion modes. Perhaps we should do some more GH experiments and publish our own version of that spreadsheet
I'd be surprised if other amps in this price range do better here actually, since the ABT2010 seems to be pretty well regarded from what I've read so far. OTOH, what is surprising is that my TV can convert 720p to 1080p with no lag, so why can't the 2310?
*shrug* anyway, while this is a bit disappointing, it's not a show-stopper for me. I can imagine how it might rain on your parade if you were counting on doing component-to-HDMI conversion for a console, though.