Under my RH 7.1 I use the word vga instead of video, and I used to use the 768 setting.
If you want these effects properly, you DO need to go through and make sure that you have frame buffer support. If you are desperate though, you can just try using one of the default ones (but they are pretty lame).
When linux loads and you see the
after a second or two it will present you with some basic options and it will ask you to select one. For a few more, you can type the word 'scan' at this point. Your screen will blink a bunch of times as it cycles through some more defaults to see if your monitor/vid card supports them. Once you find a setting you like from those, you can type
and you will see
after the line default=linux put in a line that reads vga=<your selected value here>.
If the word vga does not work for you, try the word video as indicated above.
Again, I cannot express the VAST superiority of true framebuffer support as opposed to this eye wretching desperate method I outlined for you.