If anyone else is planning to encode x264, here's some info.

These temperature statistics are in celsius, and were obatined using Gigabyte's own Easy Tune 6 Software.

The temperatures shown are during 100% load across all 8 logical cores, stressed using 1920 x 1080 x264 encodes.

3.62 GHZ (181x20), 1.152 Vcore - MAX Temp - 48 degrees
3.80 GHz (181x21), 1.232 Vcore - MAX Temp - 58 degrees

It seems that 3.6 is the sweet spot where temperatures stay fairly cool, and moving up to 3.8 GHz is only a 5% clock speed increase from 3.6, and through my tests yielded roughly the same speed increase during video encoding (4.8%), but at the cost of 10 degrees more heat.

Also, with HT on, the x264 encoding speed was roughly 15% faster during my tests. (as compared to having HT disabled.)

3.6 is good enough for me, but It's good to know 3.8 is still within safe limits, and I can use it if I really need to (which I usually won't).

FYI, coretemp, speedfan, realtemp, and cpuid all show different temperatures, so I chose to use the Gigabyte software for the tests, hoping that it'd be the most accurate, since they made my mobo.

One last FYI side note, compared to C2D (E8400) clock for clock, I usually get around 2.6x faster encoding speed with the i7 860.