Turbo modes are only used when a single core is being driven flat-out.
If you're using all cores (as you probably would if you're encoding
video) the package is generating too much heat and it won't use a turbo
mode.
The way they work is that it's more of a thermal limit then anything
else - a single core can be driven faster and generate more heat and
keep the entire chip package within its thermal limit. As more cores are
used, the turbo frequency is reduced until you get to the chip's rated
max frequency.
Jamie
On 2014-07-16 2:50 AM, Winterlight wrote:
I have yet to over clock my six core Ivy Bridge 4930k. It is rated at
3.4 GHz with Turbo at 3.9 GHz. However, when encoding with 100% on all
12 cores I am running at 3.54GHz Turbo as stated in Task Manager... so
why doesn't it rise to 3.9GHz in Turbo when it is running flat out
like this.
FYI There is plenty of quality power being fed into the CPU via the
P9X79 WS motherboard and an abundance of large radiator push pull
liquid cooling for the CPU.
