I have a Windows 7 Home Premium 64-Bit Desktop with a Intel Core i5 750@2.67GHz (4 CPUs) CPU.
I currently have Transcend (JM1333KLU-2G) JetRam DDR3-1333 2GB DIMM x2 so 4GB RAM in total.
I use Lightroom, Photoshop, work with RAW files, PCTV via Windows Media Centre, a little bit of gaming (Flight Simulator X etc).
I'm pretty content with how my PC performs but would think it was money well spent if I only noticed a mild increase in performance
A year ago 4GB RAM seemed plenty but now new laptops under $800 are coming out with 4GB RAM so it doesn't seem like much these days.
It looks like I have two available RAM slots, so I figure 2 new 4GB RAM cards wouldn't do any harm particularly because RAM ain't too expensive, around $100 for 8GB.
I'd like to stick with the same brand of RAM. This looks like it will work, could someone please confirm? http://www.pbtech.co.nz/index.php?z=p&p=MEMTRS56764&name=Transcend-JetRam-DDR3-1333-4GB-Single-DIMM
I uploaded a photo of my set-up. The current RAM cards are sitting in the blue slots, would it be ok to stick the new 4GB x2 sticks in the 2 left over black slots? Or is it better to have a different configuration like 2GB-2GB-4GB-4GB. I bet the colour of the slots mean something right?

Thanks in advance.
Steve