Caporegime
Phenom II X4's struggled to run 1600MHZ stable because the IMC was so weak, it's not out of context at all.
Thubans IMC was a lot better though.
Nothing to do with the CPU NB clockspeed.
I was just going to say my 1090T had no issues running 1866Mhz.
1600Mhz at the time, 2008, was not bad.