CF memory speed

[Eyesthruthelens]

Hi,
Just want to confirm if there is any limitation on the CF memory speed usage on the newer camera..
Looking thru the webpage, seem like current CF memory is at 40x or 52x speed.. just wonder if there is any limitation if I'm getting a second hand 20x CF card for my camera?
Can this slower speed card works on the newer SLR camera - Canon 300D? :think:

 

[mpenza]

why not check it the performance? http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

slower speeds are ok.