Zambezi is the codename for various quad, six and octa-core AMD FX processors on the AMD3+ socket. All Zambezi processors are based on AMD's 32nm SOI Bulldozer micro-architecture. Bulldozer has several interesting features and not all of it's "cores" are comparable to cores you would find on other modern x86-based CPU's.

All AMD FX processors are unlocked and do pretty well in overclocking. Besides the unlocked multiplier they are configurable in many ways (voltages, latencies, Turbo Boost etc.) via the AMD Overdrive tool.

The interesting twist in the number of "cores" is that AMD took a different approach in equipping each core. That's why AMD refers to modules. For example: the AMD FX-8120 has 4 modules (which contain 8 cores). Each module has two integer cores and one (shared) floating point core. In a nutshell the FX-8120 has 8-core to proces integer calculations and just 4 cores to procs floating point calculations. Personally I think this an interesting development as generally a lot of calculations are integer-based so it justifies having less floating-point units. Looking back at the 386DX it isn't much different: you bought a 386DX which didn't have a floating point unit at all (just like half the cores on the FX-8120). In order to speed up floating point calculations you had to buy an additional co-processor. Not many people bought it back in the day because they really didn't need one. Specific applications like CAD or mathematical operations needed a floating point unit and when Quake was released people wanted a strong floating point unit for playing games. On the right you'll see one Bulldozer module with two integer and one floating point unit.

Personally I bought the AMD FX-8120 to experience the Bulldozer. Keeping in mind that I did't want to use the CPU for gaming or mathematical operations I figured it would be a cheap 8-core that allowed me to tweak and tune it using AMD Overdrive. I have Bulldozer running without problems for 3 years now (2015) as server which also hosts you this website.