Alright i have my ps3 upsatirs on a panasonic 50inch t.v. I have my xbox downstairs ona 20inch samsung 480p. Even though i have been buying a lot of ps3 games lately i have found myself playing the xbox more. I guess the main reason for this is because most of the time my siblings are upstairs watchhing t.v. and im not really able to play my ps3 until the night. I did buy a composite cable for the ps3 for my samsung t.v. Im just wondering if this ill ruin the quality of the games on the ps3.

Expect everything to look blurred. This does make FPS generally harder. Other than that games handle the same.

expect texts on screen to be unusually small or blurred as well

additional note, I recently moved my ps3 just for a few hours now "Folding @Home" doesn't work properly anymore so...

It will be fine as long as you are enjoying the game. When I got my PS3 is didnt even have an HD TV.

Text in certain games will be nearly impossible to read and things will look blurrier. That's about the only issue.

All I can add is to say that when for some unknown reason my PS3 goes into SD mode (sometimes happens at start up), the XMB looks so bad and fuzzy compared to HD mode that there is simply no way I will ever voluntarily hook my PS3 up to anything other than a 720p or better capable TV.

I thought I'd never care about HD. But really once you go HD you never want to go back.

I used to have a non-hd tv last year and my ps3 worked fine, hd just makes it clearer. But if you cen play your ps3 more downstairs on a lower resolution then take it downstairs!

It is time for your siblings to watch movies downstairs.

If your only option is to use a SD tv I'd recommend getting an RGB cable if your tv supports it, will make all the problems like blurred text the other posters have mentioned disappear.