AMD FX-8350 Vishera 8-Core CPU Review

Vishera / Piledriver Microarchitecture

Like the recently released A-Series Trinity-based APUs that came before it, the new Vishera-based FX-Series processors leverage AMD's Piledriver microarchotecture. As we've noted before, AMD has either tweaked or revamped many of the primary functional blocks with the Piledriver microarchitecture versus the original Bulldozer which debuted last year.

The AMD Vishera Die

Although much has been changed, Piledriver is essentially an optimization of AMD's Bulldozer core. It shares the same high-level architecture as Bulldozer, but with a number of major enhancements. The same shared fetch, decode, floating point and L2 cache resources per pair of integer units is present in Vishera, however, AMD has improved their branch prediction and L2 efficiency and improved hardware prefetch as well. Piledriver cores also have a larger L1 TLB or Translation Look-aside Buffer.

AMD Made a Number of Enhancements to the Piledriver Microarchitecture

All told, AMD is claiming a combined performance increase of ~14% on the desktop versus their Bulldozer architecture. However, factor in higher Turbo Core 3.0 speed boosts and AMD is claiming larger aggregate performance gains.

The new AMD FX-Series processors is manufactured using Global Foundries' 32nm process node and consists of roughly 1.2B transistors. Although 8, 6, and 4-core variants will be available, all of the initial chips are built around the same die, which is approximately 315mm2. If you're keeping track, that makes the chip virtually identical in size to the previous-gen, Bulldozer-based FX-series.

AMD FX-Series Overview

With Vishera, AMD's Turbo Core technology offers more aggressive clock gating and overclocking. Specifically, the FX-8350 that we'll be showing you here can scale up to 4.2GHz, in single-threaded applications, but has a base clock of 4GHz with dynamic scaling as needed in single or multithreaded workloads.

The degree by which each new member of the FX series is able to Turbo varies from model to model. The 200MHz boost available on the flagship FX-8350 is actually the smallest of the initial line-up--there are other models which run at lower base clocks, but boost upwards of 600MHz.

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