RAM Upgrade for the Asus M50SV-A1

My Laptop specs:

Core 2 Duo T9300 2.5Ghz with 6Mb L2 cache
3Gbs of RAM (Specs below)
9500GS 512Mb dedicated GPU
15.4" LCD screen
Seagate Momentus 5400.4RPM HD with 8Mb cache
Intel Crestline PM965 Chipset

Make and Model:

Asus M50SV-A1

My laptop came with 3Gbs of RAM thats DDR2 667Mhz. I want to upgrade to 4Gbs and Crucial says my laptop will accept DDR2 800Mhz RAM. Others have said that 667Mhz is the fastest RAM I can use and the 800Mhz RAM will underclock itself. If I go with 4Gbs of DDR2 800Mhz RAM with 5-5-5-15 timings. I just installed a 64-bit Vista Ultimate OS and have all the services and what not tweaked for the best performance. Right now I have 64 processes running and only using 31% of all physical memory. Will I see any differences with the 800Mhz RAM over the 667Mhz and the amount?

I figured since I have a 64-bit OS I may be able to benefit a tad more. I dont know how dual channel works with RAM, but Im pretty sure the RAM is by Samsung. Everest shows it as:

DIMM3: GU332G0AJEPR8H2L4C 2 GB DDR2-667 DDR2 SDRAM (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz)

Samsung M4 70T2864QZ3-CE6 1 GB DDR2-667 DDR2 SDRAM (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz). The other 1Gb of RAM is Elpida I think.

This is what I found:

http://www.newegg.com/Product/Produc...82E16820231156

Any better deals?