After so much postponing, AMD is finally releasing its new processor series based on the “Bulldozer” architecture, the FX, featuring models with four, six, or eight processing cores. Let’s test the top-of-the-line, the eight-core AMD FX-8150 (3.6 GHz), which is placed between the Core i5-2500K (3.3 GHz) and the Core i7-2600K (3.4 GHz) in terms of price. We are also including the six-core Phenom II X6 1100T (3.3 GHz), which was previously the fastest processor from AMD. Let’s see who the winner is.
We recommend that you read our “Inside the AMD Bulldozer Architecture” tutorial if you need more in-depth information about this new architecture. For a complete list of all AMD FX processors released, please read our “All AMD FX Models” tutorial.
In a nutshell, the “Bulldozer” architecture adds the SSE4 and AVX instructions that AMD CPUs didn’t have, allows the CPU to use the higher HyperTransport 3.0 bus speeds (2.4 GHz/9.6 GB/s and 2.6 GHz/10.4 GB/s) not supported by socket AM3 processors, increases the support for DDR3 memories up to 1,866 MHz, and introduces two “Turbo” clocks. Also, all AMD FX processors have an unlocked clock multiplier, allowing you to overclock the CPU by changing this parameter. AMD FX processors require the new socket AM3+ platform.
The first (and lower) “Turbo” clock is called “Turbo Core,” which is used when the CPU “feels” the application needs more processing power, and there is still enough headroom in the CPU’s maximum dissipation power for it to increase its clock rate. For instance, if the processor TDP is 125 W and the CPU is currently dissipating 95 W, it “knows” that it still has 30 W “unused” and, thus, can increase its clock rate. In this mode, all CPU cores may be active.
The second (and higher) “Turbo” clock is called “Max Turbo,” which is used when there are unused processing cores available. In this case, the CPU puts these unused cores to “sleep,” allowing it to increase its clock rate even further.
Let’s now meet the processors included in this review.