I got a USB video card to give my development computer another monitor without getting a new video card. I started getting a headache after thinking about how they work...
The product (as advertised) uses USB 2.0 and can output 2048x1152 resolution with 32 bit color at 60Hz. A bit of math to figuire out the throughput...
2048 x 1152 = 2359296 pixels
2359296 x 32bits per color = 2359296 x 4 bytes per color = 9437184 bytes/frame
60Hz x 9437184 bytes/frame = 566,231,040 bytes per second = 540 MB/second
USB 2.0 throughput is rated at a theoretical maximum of 40MB/second.
Anyone else see the lapse in logic here? I thought maybe the packaging lies to me and it's not actually 60Hz, but to get even close to the 40MB/second max of USB 2.0 that would mean the refresh rate is only about 5Hz which would be absolutely horrible, and this does not seem to be the case. I also thought maybe it uses some type of compression - but this would essentially make high definition images look like lossy JPEG images and this is also not the case - the images look very clear.
My inner nerd is killing me here now - this device seems to have some magical properties that are not explainable. Google hasn't given me any explanations, maybe one of you can?