Question about P5Q PRO Motherboard (QVL)

Alright I have a question about this motherboard and the qualified vendors list. Initially the RAM I wanted and RAM other people suggested to me was not on the QVL for this board, even though they also suggested this board. Does a certain RAM module have to be listed on the QVL for it to work? I don't think it should have to, but I do read reports of RAM not working with certain motherboards. How can I find out if it will work or not when it's not on the list.

http://www.asus.com/999/download/p [...] 269_10.pdf

That is the QVL and I have a big question about one of the tables column headers. What is with the DIMM Socket Support (Optional) column. Here is the part I'm talking about.

Note :
A* : Supports one modules inserted into eithor slot as Single-channel memory configuration
B* : Supports one pair of modules inserted into eithor the yellow slots or
the black slots as one pair of Dual-channel memory configuration.
C* : Supports 4 modules inserted into both the yellow and black slots as two pairs of Dual-channel memory configuration

But if this part is optional why would it matter anyway? The one RAM module I wanted F2-8500CL5D-2GBPK (4th from top of QVL) is listed as only having socket support B. What if I want to upgrade later to 4GB (4x1GB) (I want to run an x64 OS soon). According to this it seems like I won't be able to b/c this RAM doesn't have socket support for type C. Please help. Thanks for your time.

Here is the board:
http://www.asus.com/products.aspx? [...] odelmenu=1
http://www.newegg.com/Product/Prod [...] 6813131299

Here is the ram:
http://www.newegg.com/Product/Prod [...] 6820231144


Thanks again for any help.