Last year's launch of AMD's FX processors was honestly disappointing. The Bulldozer CPU cores that were bundled into each Zambezi chip were hardly power efficient and in many areas couldn't significantly outperform AMD's previous generation platform. Look beyond the direct AMD comparison and the situation looked even worse. In our conclusion to last year's FX-8150 review I wrote the following:

"Single threaded performance is my biggest concern, and compared to Sandy Bridge there's a good 40-50% advantage the i5 2500K enjoys over the FX-8150. My hope is that future derivatives of the FX processor (perhaps based on Piledriver) will boast much more aggressive Turbo Core frequencies, which would do wonders at eating into that advantage."

The performance advantage that Intel enjoyed at the time was beyond what could be erased by a single generation. To make matters worse, before AMD could rev Bulldozer, Intel already began shipping Ivy Bridge - a part that not only increased performance but decreased power consumption as well. It's been a rough road for AMD over these past few years, but you have to give credit where it's due: we haven't seen AMD executing this consistently in quite a while. As promised we've now had multiple generations of each platform ship from AMD. Brazos had a mild update, Llano paved the way for Trinity which is now shipping, and around a year after Zambezi's launch we have Vishera: the Piledriver based AMD FX successor.



At a high level, Vishera swaps out the Bulldozer cores from Zambezi and replaces them with Piledriver. This is the same CPU core that is used in Trinity, but it's optimized for a very different purpose here in Vishera. While Trinity had to worry about working nicely in a laptop, Vishera is strictly a high-end desktop/workstation part. There's no on-die graphics for starters. Clock speeds and TDPs are also up compared to Trinity.

CPU Specification Comparison CPU Manufacturing Process Cores Transistor Count Die Size AMD Vishera 8C 32nm 8 1.2B 315mm2 AMD Zambezi 8C 32nm 8 1.2B 315mm2 Intel Ivy Bridge 4C 22nm 4 1.4B 160mm2 Intel Sandy Bridge E (6C) 32nm 6 2.27B 435mm2 Intel Sandy Bridge E (4C) 32nm 4 1.27B 294mm2 Intel Sandy Bridge 4C 32nm 4 1.16B 216mm2 Intel Lynnfield 4C 45nm 4 774M 296mm2 Intel Sandy Bridge 2C (GT1) 32nm 2 504M 131mm2 Intel Sandy Bridge 2C (GT2) 32nm 2 624M 149mm2

Vishera is still built on the same 32nm GlobalFoundries SOI process as Zambezi, which means there isn't much room for additional architectural complexity without ballooning die area, and not a whole lot of hope for significantly decreasing power consumption. As a fabless semiconductor manufacturer, AMD is now at GF's mercy when it comes to moving process technology forward. It simply has to make 32nm work for now. Piledriver is a light evolution over Bulldozer, so there's actually no substantial increase in die area compared to the previous generation. Cache sizes remain the same as well, which keeps everything roughly the same. These chips are obviously much larger than Intel's 22nm Ivy Bridge parts, but Intel has a full node advantage there which enables that.

Piledriver is a bit more power efficient than Bulldozer, which enables AMD to drive Vishera's frequency up while remaining in the same thermal envelope as Zambezi. The new lineup is in the table below:

CPU Specification Comparison Processor Codename Cores Clock Speed Max Turbo L2/L3 Cache TDP Price AMD FX-8350 Vishera 8 4.0GHz 4.2GHz 8MB/8MB 125W $199 AMD FX-8150 Zambezi 8 3.6GHz 4.2GHz 8MB/8MB 125W $183 AMD FX-8320 Vishera 8 3.5GHz 4.0GHz 8MB/8MB 125W $169 AMD FX-8120 Zambezi 8 3.1GHz 4.0GHz 8MB/8MB 125W $153 AMD FX-6300 Vishera 6 3.5GHz 4.1GHz 6MB/8MB 95W $132 AMD FX-6100 Zambezi 6 3.3GHz 3.9GHz 6MB/8MB 95W $112 AMD FX-4300 Vishera 4 3.8GHz 4.0GHz 4MB/4MB 95W $122 AMD FX-4100 Zambezi 4 3.6GHz 3.8GHz 4MB/4MB 95W $101

The table above says it all. TDPs haven't changed, cache sizes haven't changed and neither have core counts. Across the board Vishera ships at higher base frequencies than the equivalent Zambezi part, but without increasing max turbo frequency (in the case of the 8-core parts). The 6 and 4 core versions get boosts to both sides, without increasing TDP. In our Trinity notebook review I called the new CPU core Bulldozed Tuned. The table above supports that characterization.

It's also important to note that AMD's pricing this time around is far more sensible. While the FX-8150 debuted at $245, the 8350 drops that price to $199 putting it around $40 less than the Core i5 3570K. The chart below shows where AMD expects all of these CPUs to do battle:

AMD's targets are similar to what they were last time: Intel's Core i5 and below. All of the FX processors remain unlocked and ship fully featured with hardware AES acceleration enabled. Most Socket-AM3+ motherboards on the market today should support the new parts with nothing more than a BIOS update. In fact, I used the same ASUS Crosshair V Formula motherboard I used last year (with a much newer BIOS) for today's review:

The Test

For more comparisons be sure to check out our performance database: Bench.