Mixing Memory (8gb x 4gb x 4gb)

I currently have 8gb (4gb x 4gb) in my desktop (http://www.corsair.com/us/memory-by-product-family/vengeance/vengeance-8gb-dual-channel-ddr3-memory-kit-cmz8gx3m2a1600c9.html). I am into 3D rendering and I need to increase the amount of memory in my computer. I found a great deal on an 8gb stick (http://www.corsair.com/us/memory-by-product-family/vengeance/vengeance-8gb-ddr3-memory-kit-cmz8gx3m1a1600c10.html) but I am unsure if it would be optimal to do so. I noticed the timing is off on the two. Also, my motherboard supports four slots and I have the 4gb sticks in the primary 1,3 slots. Would I put the 8gb in the 2 slot? Or would I need to buy 2 8gb sticks for it to be even worth it? Any help would be great! And soon, the deal ends today.

What MB and CPU do you have? Need to know this to establish if you can use 8 gig modules.

 

Please keep in mind that mixing memory is not supported or suggested by Corsair. There is just now to tell how any two random kits/modules are going to play with each other. If your system can use 8gig modules and you decide to try this, there are no guarantees that it will work. Really your best bet would be to replace your memory with one matched kit of the capacity that meets your needs.

I have the AMD FX-8350 CPU and the M597 Mb. I'm pretty sure it supports it. I have decided not to buy it though because I cannot afford to buy two 8gb sticks right now. Thanks for the information!