Not sure how "real-time" the dazzle box is. I know when I tried to run a video capture card in my desktop, that was seperate from the actual video card (ie: an add-in card), there was a good 2 - 3 second lag from real-time to what actually played on the screen. And there's considerably more bandwidth on a PCI bus than there is on a USB bus, even USB 2 can't pass data nearly as fast as PCI.
Now, when I got an all-in-one card (tv tuner on the video card), the lag was reduced from 2 - 3 seconds to less than a 1/4 second. It was playable at that rate, but annoying on any games that required split-second reactions.
So, the gist is, you probably won't find anything USB based that will adequately pass the video data to the screen to play video games on.
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