Asus P5QL-SE and an 800mhz memory

Hello and welcome to the forums  
Yes it should work fine,when its compatible with 1066 then its compatible with anything lower than 1066 too like DDR2 800....

The memory support list (you probably didn't download it) includes 667 MHz, 800 MHz and 1066 MHz memory modules. Geil have several modules listed.

thanks guys and yep i did take a look at the support list but before asking, i did some research and on some other forums, the people told other people asking the same question as i did to get a new ram, and i was confused. and thanks for the replies! there are only very few 1066RAM here in our country that is why i want to stick with a 800mhz one