I managed to get a full, stable 5.0 GHz out of my sample FX-8350. Most of my testing showed that these new AMD CPUs are, like previous chips, a bit sensitive to temperature when it comes to overclocking; however, I found that I only had to increase the CPU base voltage a bit and nothing else, which is a nice change over other CPUs right now. I even managed to get a higher overclock out of my AMD Performance Edition memory. It topped out at 2400 MHz with the FX-8350, rather than the 2133 MHz I got with the FX 8150.
My much older FX-8150 chip also reached that 5.0 GHz mark of course, but it was not as capable when it came to ram overclocking. I had to, even as it was, increase the northbridge voltage to get that 2133 MHz stable, which shows that there are definitely some improvements in the memory controller - nevermind the efficiency increases shown in the benchmarks.
Even though there is a default clock increase between the FX-8150 and the FX-8350, there is more than just raw frequency to the overall performance increase that the FX-8350 offers. Here, with Turbo and other power-saving features disabled and an increased clockspeed, we get a chance to see what improvements AMD offers through optimizations alone. It seems very obvious that part of it is due to better memory control and its higher possible system memory overclocks - at least with the sample I have, but those other changes to the core design have definitely had their effect as well.
OC Power Consumption
Power consumption when overclocked improved quite a bit, although similar temperatures and similar CPU clocks were reached. I couldn't be more impressed, but that is, at the same time, still more power than we find on current Intel products. It will be interesting to see this design transfer over to 22nm or whatever process AMD adopts next. I was amused to find out that both CPUs just need 1.5 V to reach 5.0 GHz, but the FX-8350 seems to draw less current to keep that clock stable.
In the end, I think the numbers speak for themselves. AMD did a pretty good job fixing things up, especially once you get the core speeds up. Process improvements will hopefully allow AMD to ramp the raw speed of these chips up since they really seem to perform best when pushed to the limit.