Okay on Photobucket. AMD usually only makes one BLACK edition CPU per class (x2 , x3 , x4) so the 7750 are most likely drying up.
Overclocking is easy. But name brand PCs don't have such options as that is controlled by the BIOS/software through the motherboard. Its all in the timing. Such as the AMD 7850 CPU default is a 200mhz clock with a X 14 Multiplier - 2800Mhz.
In the OLD days of 486~P1 CPUs, they were open. It wasn't so much a problem with end-users OCing the CPU, but under-handed PC shops doing it. Thus, they could sell a P75 (P1 75Mhz) CPU in a computer and sell it as a P100 system, making an extra $25~200 for a single sale. I've seen vendors sell unmarked CPUs in bins of 75/90/100... most likely, they were all P75s - their prices were below my costs for OEMs.
So AMD & Intel locked the CPUs multiplier and starting building in ID code. Because the OC P75 would come up as a P100 during the BIOS boot screen. While today, my $180 Q6600 (2.4Ghz) will always come up as a "Q6600" even thou its 3.0Ghz and performed liked its Q6850 CPU at $1000. Of course there are no Q6xxx CPUs anymore. Todays C2Q 3.0 is the Q9650 at $320~350. Its only a bit faster than my CPU and requires less power.
So... AMD sells BLACK edition CPUs were are unlocked CPUs, but retain their ID.
To OC my Q6600, I raised the clock rate from 266mhz > 333mhz. I am locked at X 9. With such CPUs, you want a HIGHER multiplier to get the most per clock.
So with the AMD 7850, I went from 14x to 14.5x, raised the CPU clock from 200mhz to 220mhz to get about 3.2Ghz (400mhz OC) I did hit 3.3Ghz... but I like to tone it down. You also need to watch the CPU TEMP... before and after (idle and load) to make sure the cooling system can handle the changes. Going up a few Cs is fine, but having a jump of 10+ is bad. I couldn't hit 3.4~3.6 without raising the voltage to the CPU - which I am not willing to do for long. The heat from the CPU will spike and your chances of killing the CPU goes up. Also, the CPU will simply die faster... 1-2 years, rather than 6~15 years.
When you build your own PC, you'll see these options in the manual and in the BIOS.
You don't need to make some high-tech water cooling system to OC. Why spend $100~300 to gain an extra 100~400mhz? For some, its for fun. But water cooling does FAIL. Then theres liquid nitrogen... You can get the CPUs up to 5~6Ghz... but of course its useless for a desktop computer system
PS: If you OC too high - the PC will either fail to boot or you'll get errors. Turn off the PC, BIOS will reset to defaults... and use lower settings. 3.2Ghz on the 7850 takes a few seconds.