The Bulldozer CPU

Let's begin with AMD's line-up, here we will talk about the Bulldozer CPUs that are meanwhile available. With Bulldozer AMD has seven models in its portfolio. Two of them are eight-core CPUs, one is a six-core processor and finally another one is a quad-core model. These AM3+ processors are compatible with AM3 motherboards. However you will have to check the website of your motherboard manufacturer to update to latest BIOS version and check if there is a version that supports the new FX processors.

Looking at the specifications, they have a TDP of 95 Watts and 125 Watts for the most powerful of them. They also have a L2 cache that is proportional to the amount of cores and 8 MB of L3 cache. All those FX processors are ''Black Editions'', which means that the CPU multiplyer is unlocked. Furthermore all CPUs have a Turbo feature. The first step, which is called Turbo Core does affect all the CPUs cores while the second step only affects half of total amount of cores, which has the consequence that the dissipation power remains withing the TDP limit.

At the time this article has been written the cheapest AMD FX CPU costs CHF 116.- (est. EUR 97.-). The price goes all the way up to CHF 217.- (est. EUR 180.-) for the high-end FX-8150. The FX-4170 we tested here costs CHF 148.- (est. EUR 123.-).

AMD started from scratch to make this new architecture way different from what we used to see on a Phenom II for exemple. The major change is the sharing of computing units. By computing units we mean the fetching unit as well as the decoding unit, the Floating Point Scheduler and finally the L2 cache. The image above shows you a dual core CPU while the image below shows you how a Bulldozer's module (2 physical cores) is organized.

Theorically this lowers the CPUs manufacturing cost by lowering the amount of transistors this should also result in lower power consumption and still maintaining maximum performance. In practice it's another world. The FX Bulldozer's architecture is performing very well for multithreaded applications and for optimized software as well as server and supercomputers. Unfortunately you and me we're no professional users, we're consumers and this is a entirely different target market. We do not tailor the software to our needs. We have software the is how it is and for us a CPU should perform best with the software we have. But we'll focus on that in the performance part of this review. To stay plain and simple, this architecture can be seen like Intel's Hyperthreading but better. Better because hyperthreading is based on one physical and one logical core. Bulldozer on the other hand offers two physical cores which offer an 80 percent scaling. Could it be seen as a quadcore CPU with "HyperThreading" ? No, although it's not a "real" octacore processor as well. We like to say it's a processor with four modules.