AMD FX-8350 Review: Does Piledriver Fix Bulldozer's Flaws?

Last year, AMD launched its Bulldozer architecture to disappointed enthusiasts who were hoping to see the company rise to its former glory. Today, we get an FX processor based on the Piledriver update. Does it give power users something to celebrate?

As someone who reviews computer hardware, the challenges facing a business matter a lot less to me than the products it sells. We can all agree that the last year was pretty awful for AMD’s processor team, beginning with the power-hungry Bulldozer-based FX CPUs that slowly slid down in price over 12 months in response to a more compelling family of third-gen Core processors from Intel. But every delivery to my SoCal lab represents an opportunity. Chatter about mismanagement, layoffs, and a troubled past matter little in the evaluation of a new CPU. So, let's get down to business.

Sometimes it’s possible to predict the outcome of a story. Had AMD shipped an FX-8170 running 200 MHz faster than its former flagship, I would have guessed that it’d exhibit the same issues with lightly-threaded workloads, it would probably outperform a Core i5-2500K in more intensive tasks, but its power consumption would probably look pretty nasty compared to modern 77 W Ivy Bridge-based chips.

Instead, we have an FX-8350, which centers on the same Piledriver architecture as the Trinity-based APUs introduced less than one month ago. Experience tells us that, per core and per cycle, Piledriver can be as much as 15% faster than a Bulldozer-based design. Add to that the fact that FX-8350 operates at least 400 MHz faster than FX-8150. Oh, yeah. And Ivy Bridge only gave Intel’s line-up single-digit gains. There’s every chance that today’s performance comparison is going to be a lot more interesting than the overwhelmingly negative judgment passed on FX-8150 one year ago.

Meet The Piledriver-Based FX Family

In a faithful return to its Bulldozer approach, AMD sent out the fastest model in its new line-up for review, but is actually introducing eight-, six-, and four-core configurations. Of course, we know they all center on the Piledriver architecture, but the SoC itself is referred to as Vishera, and it’s still branded as FX.

A complete Vishera processor measures 315 square millimeters and is composed of 1.2 billion transistors. Those are the exact same figures given for Zambezi, the previous-generation SoC based on AMD’s Bulldozer architecture. Whatever alterations the architects made—from resonant clock mesh technology to ISA extensions or even a larger L1 DTLB—surface area and transistor count don’t change enough to move the dial on those contextually-irrelevant but interesting-to-know-anyway specifications.

AMD's 2012 FX Family

Core Count
Base Clock
Max. Turbo
NB Clock
8C / 8T
4.0 GHz
4.2 GHz
2200 MHz
125 W
8C / 8T3.5 GHz
4.0 GHz
2200 MHz125 W$169
6C / 6T
3.5 GHz
4.1 GHz
2000 MHz
95 W
4C / 4T
3.8 GHz
4.0 GHz
2000 MHz
95 W

Two of the four SKUs boast eight integer cores, or four Piledriver modules, however you choose to label AMD’s compute units. The flagship, FX-8350, features a base clock rate of 4 GHz. Turbo Core technology is able to push that to 4.2 GHz in lightly-threaded workloads, though most of the chip’s speed-up undoubtedly comes from its default state. How much does Turbo Core really do for FX-8350? Not much. In iTunes, our single-threaded benchmark finishes three seconds faster with the feature on.

An FX-8320 drops the base clock rate to 3.5 GHz, though Turbo Core pushes that to 4 GHz under defined thermal limits (a 500 MHz speed-up is likely more meaningful to FX-8320). Both eight-core models include 8 MB of L2 cache (split into one shared 2 MB slice per module) and 8 MB of L3 cache (shared between all four of the SoC’s modules). AMD is suggesting a $195 price tag on FX-8350 and a $169 price on FX-8320.

FX-6300 comes equipped with three active modules (six cores) and drops pricing all the way to $132. A 3.5 GHz base clock rate helps take advantage of the architecture’s strengths in threaded apps, while a 4.1 GHz peak Turbo Core setting tries to compensate for lackluster single-threaded speed. Like the four-module parts, FX-6300 exposes 2 MB of shared L2 per module (totaling 6 MB in this case) and a shared 8 MB L3 cache. Fewer active resources (along with a slightly slower 2 GHz northbridge clock) allow FX-6300 to fit within a 95 W thermal ceiling, down from the 125 W limit imposed by both FX-83x0 processors.

A lone dual-module CPU, FX-4300, is also rated for 95 W. Its base 3.8 GHz clock rate is sped up to 4 GHz in lightly-threaded apps, and a 2 GHz northbridge frequency matches the FX-6300. A drop to 4 MB of shared L3, however, and a price tag just $10 under the triple-module chip will likely encourage most folks to spend the extra $10 bucks.

Although AMD’s architecture doesn’t seem particularly bandwidth-starved, Vishera’s dual-channel DDR3 memory controller officially supports 1866 MT/s data rates. Frankly, we’d rather use lower-latency 1600 MT/s modules to maximize value, particularly since our results show that you don't gain any performance (outside of Sandra 2013 Beta) after spending more on faster memory.

The entire FX line-up also features an unlocked ratio multiplier, which serves to simplify overclocking. Is Vishera scalable enough to make tuning worthwhile? What do you think about 5.125 GHz using a closed-loop liquid cooler?

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  • bemused_fred
    Wha-? Progress? An actually half-decent CPU? From the failed bulldozer architecture? Not bad, AMD, not bad at all. This is going to make the market muuuuuch more interesting....
  • bemused_fred
    (Still not great for gaming though. Guess we'll see what the 8370 brings.)
  • Robi_g
    Mucho good AMD. Now make it better
  • silverblue
    Do they sell cheap Piledriver CPUs there?

    If not, naff off.
  • Anonymous
    To be honest those results are quite good. Even though I prefer Intel big thumbs up for AMD for putting together a very vell performing CPU. Good to see them back ;)
  • Anonymous
    To be honest those results are quite good. Even though I prefer Intel big thumbs up for AMD for putting together a very vell performing CPU. Good to see them back ;)
  • Anonymous
    For anyone with a 990 board still sitting on a Phenom it's a great way to finally upgrade a little for a cheap price. It's hard to recommend for someone building a new PC from scratch though, this has to be pretty much the last kick at the can for AM3+ (other than maybe one slightly faster chip say 8360 or 8370) so even though it competes well for the money it will likely be a non-upgradable option. Who knows though, 1155 might be End of Life too with only one or two more processors left in each stream (3780K and 3580K probably). I'm thinking even 2011 isn't going to get much better: IvyBridge E will only show the same 5% bump on Sandy E that Ivy did on Sandy and then 2011 will come to an end.

    If you already have a current gen system (1155, 2011, AM3+) It really seems like there is no reason at all to upgrade until the next gen comes out for all of them. The difference in real world use is hardly noticeable for any of the upgrade paths. I think the problem is that software is really not pushing processor tech any more, hell a Q6600 on a good board with DDR2 can still run almost anything you throw at it and run it fairly well, not everyone is rendering and video editing.
  • Robi_g
    btcstore15input this URL:( )you can find many cheap and high stuffBelieve you will love it.WE ACCEPT CREDIT CARD /WESTERN UNION PAYMENTYOU MUST NOT MISS IT!!!

  • sam_p_lay

    If 5 people vote that down though, it disappears from the comments list (well it's collapsed by default anyway).
  • doveman
    I've learnt that the poor single-threaded performance of AMD CPU's severely hinders some games, such as ArmAII-OA, so it's disappointing the FX doesn't fix that. Not that I could have afforded to build an Intel system instead (nor can I now) but it would have been nice to have been told before buying the game that it would only run at 13-23fps much of the time, rather than them pretending an Athlon 64 X2 4400+ was "Optimal" (I have a Phenom II X4 955 @3.8Ghz, 16GB RAM and a 2GB 6950).

    Oh well, maybe ArmA3 will work properly on AMD!
  • Anonymous
    It's good news that the architecture has gotten better. However still disappointing that an 8 core & 8 threaded CPU still can't quite catch the previous generations of i7's performance clock for clock. & only can when overclocked itself (which like you say counts for little in comparison when you consider the i7 blows it out the water when that too is overclocked & is only a 4 core 8 threads CPU!). Just throwing extra cores at the solution & still coming up short.
  • emilper
    Try the Bulldozer or the Trinity (don't have a Vishera yet) on Linux compiled with SMP support and you'll regret paying three times the price for a processor made by the competition. Visheras did not make it here yet, but I already bought the case for it :)

    AMD is right to bet on the mobile and server/workstation market (where Unix and GNU/Linux rule) and on mobile devices (where Android/Linux rules) ...