Thinking about expanding memory, but existing RAM can no longer be found?

As the title says, I have not been able to another set of RAM, of the same model number to purchase as an expansion to my existing RAM. I don't particularly want mismatched pairs.

I bought the 2*2GB package in hopes of another 2*2 later on. Model: CMT4GX3M2133C9.

 

I reside in the UK, and have checked overclockers.co.uk, scan.co.uk, novatech.co.uk, and Corsair.com's product page (only found it actually existed in the support section of the website.)

 

I was wondering where I may be able to find a retailer for this product or if it has been discontinued for any reason? I do not want to replace existing RAM.

Corsair does not suggest or support mixing of memory . Even two kits of the exact same part number has a pretty good chance of not working together or at rated speeds. Your best bet would be to replace what you have with a new matched 8 gig kit.

Shame. Any advice on RAM configuration? 2*4GB or 4*2GB? I was under the impression that 4*2GB would yield higher efficiency due to 4 DIMM's being able to be accessed at once rather than 2 DIMM's being accessed with 2 times less speed, but after reading around, opinions seem to suggest differently from my understanding; any clarification please?

4*2 GB isn't more efficient. 4*2 GB is better because it's less stress on the memory controller.

Thanks for the advice, much appreciated.

 

8gb-(2x4gb)-corsair-ddr3-dominator-gt-pc3-17066-(2133)-non-ecc-unbuffered-cas-9-11-9-27-dhx-xmp-15v has been ordered based upon advice.