which ram for Asus M6R ?

Hi guys, sorry i'm pretty new to this whole notebook thing..ive only dealth with desktops before.

I'd like to upgrade the ram on my Asus M6R. This is the webpage for anyone unfamiliar with it:

http://au.asus.com/products4.aspx?modelmenu=2&model=40&l1=5&l2=24&l3=128

It says it comes with DDR-333 ram, I would like to put in some
1GB PC-4200 (533MHz) 200-pin SO-DIMM DDR2 RAM OEM
or
1GB PC-4200 (533MHz) 200-pin SO-DIMM DDR2 RAM Corsair "VALUE SELECT" (USA), 128Mx64, CL4.

I'm guessing the only diff is the brand name...which its probably worth paying the extra $30 or so for right?
Currently its at 512MB, im opening it up tonight for a look to see if theres even a slot free.. (as i think the shop upgraded from 256..knowing my luck they probably just put another 256 in). (the website says there are 2 slots availible..and 2Gig is the max you can upgrade to)

Will I notice a big improvement from my 512MB to 1G and even more with 2G ? I'm currently using this laptop as my only computer and it stays on most of the time (want it to be on constantly...reset every one week or so..)...it has a shared ATI graphics card, i think that might be eating up most of the memory...I'd prefer not to set it lower than 128MB as i play the occasional games. I don't use it for work though, but I would like it to be ABLE to run some CAD softwares if incase I do need to..

Thank you in advance, I really appreciate it.

 

I think you don't need to buy 533mhz DDR2, instead go for DDR1 because I doubt it will utilize the extra speed, since the chipset is the older 855 one.

As for 512 -> 1024, there is quite an improvement. 2GB is usually overkill though.

 

Thanks for the response coriolis.
im just looking at some prices, it seems that..
DDR333 Corsair PC2700 is slightly higher priced than the previous DDR2 i mentioned?
If i get the other one, will it run at DDR1 ?