Recently, I just got a new Acer v3 551g laptop. Disliking all of the bloatware, I did a fresh install of Windows. After all was set and good, I wanted to see how hot the laptop would get, so I ran Prime95. Here, I noticed that the cores were not going up to 1.9GHz. Intrigued, I set the affinity to 1 core, and noticed that it was not turboing to 2.8GHz.
I agree. Make sure Windows is in balanced mode and as well check to make sure you have any power management drivers installed. I haven't seen anything beyond the chipset for AMD but sometimes there is a ACPI module driver that needs to be installed.
As well if its on battery power, it may have settings that reduce power usage to maximize battery life (such as disabling Aero ect)