Introduction
Contents
Today, AMD is releasing its second-generation of FX CPUs, dubbed “Vishera.” The FX-8350 is currently the highest-end model available, running at 4 GHz and costing USD 195. Let’s see how it fares against its main competitor, the Core i5-3470 (3.2 GHz, USD 200). We also included in our comparison the AMD CPU that used to be the highest-end model, the FX-8150 (3.6 GHz, USD 190 currently, USD 280 at its release), and what was then its main competitor, the Core i5-2500K (3.3 GHz, USD 220). For curiosity sake, we also added to the comparison the Phenom II X6 1100T (3.3 GHz, USD 190 when it was sold), which used to be AMD’s fastest CPU before the release of the FX family.
The new FX-8350 uses the socket AM3+, and is compatible with any socket AM3+ motherboard, although the motherboard may need a BIOS upgrade to correctly recognize the new CPU.
Figure 1: The AMD FX-8350 processor
The second-generation FX processors are based on the new “Piledriver” architecture, which is basically the “Bulldozer” architecture used by the previous generation with a few tweaks.
In the tables below, we compare the main features of the CPUs included in our review. All CPUs support the SSE4 instruction set (both SSE4.1 and SSE4.2) and the AVX instruction set, except for the Phenom II X6 1100T, which doesn’t support these instruction sets. On the Phenom II X6 1100T, the HyperTransport bus (which is used to connect the CPU to the chipset) works at 2 GHz (8 MB/s); the memory controller works at 2 GHz, while on the FX CPUs the HyperTransport bus works at 2.6 GHz (10.4 GB/s) and the memory controller works at 2.2 GHz. All CPUs support a “turbo clock” technology, which increases the CPU internal clock as needed. The Core i5 processors included in our comparison do not support the Hyper-Threading technology.
It is important to understand that with the FX CPUs from AMD, each pair of CPU cores share the same front-end engine (i.e., the fetch unit, the L1 instruction cache, and the instruction decoders). So, each pair of CPU cores is part of the same “module,” and the FX-8350 and the FX-8150 are comprised of four of these modules. With the other CPUs included in our review, every core is a complete CPU, each with its own front-end engine.
| CPU | Cores | HT | Internal Clock | Turbo Clock | Max Turbo | Core | Technology | TDP | Socket | Price |
| FX-8350 | 8 | No | 4.0 GHz | 4.2 GHz | 4.2 GHz | Vishera | 32 nm | 125 W | AM3+ | USD 195 |
| FX-8150 | 8 | No | 3.6 GHz | 3.9 GHz | 4.2 GHz | Zambezi | 32 nm | 125 W | AM3+ | USD 190 |
| Phenom II X6 1100T | 6 | No | 3.3 GHz | 3.7 GHz | 3.7 GHz | Thuban | 45 nm | 125 W | AM3 | NA |
| Core i5-2500K | 4 | No | 3.3 GHz | 3.7 GHz | 3.7 GHz | Sandy Bridge | 32 nm | 95 W | LGA1155 | USD 220 |
| Core i5-3470 | 4 | No | 3.2 GHz | 3.6 GHz | 3.6 GHz | Ivy Bridge | 22 nm | 77 W | LGA1155 | USD 200 |
Prices were researched at Newegg.com on the day we published this review, except for the FX-8350, which is the price provided by AMD. The Phenom II X6 1100T is no longer sold. TDP stands for Thermal Design Power and states the maximum amount of heat the CPU can dissipate. The CPU cooler must be capable of dissipating at least this amount of heat.
Below you can see the memory configuration for each CPU.
| CPU | L1 Cache (I + D) | L2 Cache | L3 Cache | Memory Support | Memory Channels |
| FX-8350 | 64 kB per module + 16 kB per core | 2 MB x 4 | 8 MB total | Up to DDR3-1866 | Two |
| FX-8150 | 64 kB per module + 16 kB per core | 2 MB x 4 | 8 MB total | Up to DDR3-1866 | Two |
| Phenom II X6 1100T | 64 kB + 64 kB per core | 512 kB per core | 6 MB total | Up to DDR3-1333 | Two |
| Core i5-2500K | 32 kB + 32 kB per core | 256 kB per core | 6 MB total | Up to DDR3-1333 | Two |
| Core i5-3470 | 32 kB + 32 kB per core | 256 kB per core | 6 MB total | Up to DDR3-1600 | Two |