RAM Question: Combining different pin numbers

[JimmyCracksCorn]

I want to upgrade my RAM. Currently I have 512MB of SDRAM which is starting to blow with newer games.

My MOBO has 4 slots. 2 are for 168 pin SDRAM and the other two are for 184 pin DDR SDRAM. Now my question is, can I buy two more chips of the 184 pin DDR RAM and use it in conjunction with the 168 pin SDRAM I already have?

I've heard that if you combine with faster chips, the clock speed goes down to meet the slower ones. If this is the case, thats fine because I really just want more RAM now... I can upgrade all my chips later.

And if it makes any difference, this is my MOBO:

http://www.biostar-usa.com/mbdetails.asp?model=u8668

Thanks.

Edit: And oh yeah, does anyone have any recommendations for places to buy cheap RAM online?

[JimmyCracksCorn]

Come on, someone must know...

[JimmyCracksCorn]

Also, how can I tell if my motherboard wants ECC or non-ECC RAM?

[Urban Ranger]

First question: probably not.
Second question: EEC RAM is more expensive and is used mainly in servers.

[centrifuge]

Jimmy go to www.crucial.com, type in your mobo and they'll give you a list of compatibles. Crucial is the only way to go !!!

[Urban Ranger]

I use corsair