Hi,
I understand and to be totally honest and with hindsight I probably wouldn't have gone for the 1600Mhz memory but with the 1333 RAM instead.
By default the Phenom ii CPU's Memory Controller is set for 1333 Mhz memory or slower. Anything above that becomes an overclock (they don't tell you that in the advertising!) If you put 1600 Mhz RAM into your system it will automatically downgrade to 1333 Mhz and getting it to run happily at the rated stock speed involves playing with BIOS.(Gigabyte don't tell you this either, you can't plug and play with the RAM like you used to.)
Another thing to consider is the actually advantages of going for the slightly faster RAM and again, these are not as great as people imagine in real life. If you want to spend your time playing around with benchmarking software and apps., you will get some nice figures but, in everyday, normal computing you actually gain more by bumping the speed of the CPU a bit and, with the 1090T there is plenty of room to manoeuvre.
If you are looking to run 8 Gig of RAM without any hardship, go for 1333 Mhz modules. You will not notice any real loss of performance but you will gain by having a more stable and reliable system.
Hope this helps you understand the situation a little more.