Three of the test-cards offer a video out option. Now this feature is mainly interesting for two things. The most important one is probably the ability to play games on your big screen television. In this case please consider that a resolution of more than 800x600 is neither possible nor sensible. For US and Canadian citizens using TVs with the NTSC-standard, it's even questionable if a resolution of more than 640x480 is making sense. NTSC is only displaying 480 lines, so that the 600 lines of the 800x600 resolution cannot get displayed properly anyway. The European PAL is providing 600 lines, which makes a 800x600 screen look a lot better than on NTSC. Still, the 480 or 600 lines are both only a theoretical maximum, in reality the TV output resolution is about 5-10% less.
The second use of video out is using the computer as your DVD-player. In this case you don't have to care about the above said.
The most interesting thing about video out is its quality. Does it flicker? Can you recognize everything? Does it fill the TV-screen, or is it too large or too small? Can you use your computer monitor at the same time and if yes, do you have to use the low TV refresh rate?
To give you some kind of idea what it looks like, I've captured the video output of each card with the Matrox Marvel G200. The Marvel is excellent at capturing snap shots and highly impressive for video editing. You can see a good difference between the three cards, but please note that the Asus card is PAL, the other two are NTSC.
Diamond Viper V550
STB Velocity 4400
The quality of the Asus card is clearly best, but it has got an advantage due to the PAL format. Diamonds card needs to be adjusted to maximum flicker reduction, otherwise the picture flickers terribly. The Velocity 4400 flickers permanently, regardless if you switch the flicker filter to 'for games' or 'for text'. The V3400TNT/TV is also the only card that can display on the TV as well as on the computer monitor at the same time. You can even adjust a high refresh rate for the monitor, leaving the TV picture untouched.
The Asus V3400TNT/TV is clearly the most convenient card for video out, but I cannot say if the quality of it is indeed better than of the Diamond card, because I would need to test the NTSC-version of the V3400TNT/TV for that. The Diamond Viper V550 is clearly superior to the STB card when it comes to video out.