Two months ago when we tested the top desktop Bulldozer processor, we concluded that it turned out a big disappointment. The results of our today’s FX series testing, including lower-cost CPU modifications, didn’t change out opinion. Processors on Bulldozer microarchitecture with four or six cores are designed exactly the same way as their eight-core counterparts. Pairs of cores are combined into modules and share some of the resources. And even though this approach can be implemented at a lower transistor count and allows producing relatively inexpensive monolithic semiconductor dies, the actual performance-per-core drops making the final product not so well-balanced in the end. As a result, AMD can sport many processor cores, but in reality this number doesn’t mean anything. Our tests showed that a pair of Bulldozer cores can compare in performance only against one Sandy Bridge core, and only with certain allowances and only in applications that split the load in parallel threads. This is where the low performance in most applications comes from.
The flagship eight-core CPU in the FX family, AMD FX-8150, in most cases can’t catch up even with the quad-core Core i5-2500, performing well only in few selected applications for 3D modeling and during video transcoding.
Slower eight-core modification, AMD FX-8120, looks even less convincing, because it has significantly lower clock frequencies. In terms of performance, this processor ranks even below the quad-core competitor solutions. Moreover, FX-8120 is also slower than the top previous-generation AMD CPU – Phenom II X6 1100T.
Six-core FX-6100 is similar in speed to mainstream Phenom II X6 processors, and in comparison to competition, it falls between top Core i3 and junior Core i5 CPUs. Besides, in most general-purpose applications, including games, its performance is closer to that of dual-core Core i3.
The junior desktop Bulldozer CPU, FX-4100, looks more like a more up-to-date alternative to the junior Phenom II X4 processors, i.e. it is often even slower than Core i3.
Of course, performance is not the only feature of the CPU that matters to the end-users. AMD has always used pricing strategies to their advantage making their not very fast products a good buy almost all the time. However, in case of the new FX series, they seem to have lost touch with reality. Bulldozer processors are obviously overpriced, their prices are inadequate for the level of performance in general-purpose tasks that they can deliver. AMD may be betting on enthusiasts who care about energy-efficiency and who won’t be able to find an Intel product with overclocking capabilities in the sub-$200 price range. However, in our opinion this argument won’t save even the very junior FX models, especially since it is impossible to unlock the disabled cores in FX-6100 and FX-4100 CPUs.
It turns out that the only one who may benefit from the upcoming migration from Phenom II to the new FX family is AMD. Bulldozer microarchitecture allows the company to stop using old manufacturing process for their semiconductor dies and move on to the new cores with lower production cost. However, the end users won’t win in this situation. FX CPUs that are coming to replace the good old Phenom II processors are not faster or cheaper than their predecessors. Therefore, until processors on new Piledriver microarchitecture come out, the new FX are of no real interest to AMD fans and Phenom II owners. FX CPUs are also hardly appealing for the new systems: Intel’s Core i5 and Core i3 processors can offer better combination of price and performance in a wide range of tasks with only a few exceptions such as video transcoding in x264 codec and selected 3D rendering applications.
So, we can’t recommend getting involved with the new FX CPUs from AMD at least until they revise their pricing. And even though there are claims that desktop Bulldozer processors are selling pretty well, we can’t imagine who could really be investing their hard-earned cash into these products.