I have i5 4440 3.1Ghz, the turbo boost doesn't work while running Cinebench R15, it should clocked up to 3.3Ghz but when I run other programs I see turbo working, why is that? I scored 477 in cinebench and using realtemp for monitoring temps and cpu clock
Cinebench will use all cores at 100%. Turbo boost raises or lowers your clock speed based on temp and the number of cores in use. The more cores that are used, the less of a boost. You will get the highest boost speed when only one core is in use.
What thedealer says is true as a matter of default settings. Certain motherboards, however, will override that limitation and allow you to set the boost clock of each core, which you can manually set to the stock boost clock. Doing that can allow all cores to boost simultaneously if your motherboard supports it. Certain Asus motherboards support that for "k" skew chips, but I don't know whether non-k chips will have anything to do the same. Just letting you know in case you want to look into it more.
That very limitation has lead me to actually swap a motherboard. There was more performance gain from it than upgrading my CPU to the next generation, and it the motherboard was less expensive than a new chip.