AMD's FX-8350: Power and Performance Better Than You've Heard
It’s very easy to be dismissive of AMD’s mainstream FX processors based on the Piledriver core. Intel has been beating AMD on every front but price for a couple of generations now, owing at least some of their success to being consistently one generation ahead in manufacturing process technology. Meanwhile, the Bulldozer microarchitecture and its descendants have had an unpleasant uphill climb. Power consumption, performance per clock, it all takes its toll. Arguably AMD doesn’t make things better for themselves by releasing the FX-9590 and FX-9370, chips with virtually no overclocking headroom and staggering 220W TDPs. And finally, FX chips still rely on the antiquated 900 series chipsets, which lack support for PCIe 3.0.
Suffice to say, there’s a laundry list.
However, we took AMD’s most popular CPU, the FX-8350, for a test drive and found that things aren’t anywhere near as bad as the press and benchmarks might lead you to believe. Quite the opposite, actually.
As we’ve done recently with Intel’s Haswell-E and Devil’s Canyon parts, today we’re doing a power-to-performance test to see just how much power an AMD FX-8350 consumes when faced with gaming and multimedia tasks.
Our testbed consists of:
- CPU: AMD FX-8350 (4 GHz, turbo to 4.2 GHz, 125W TDP)
- CPU Cooler: Corsair Hydro Series H100i
- Motherboard: Gigabyte GA-990FXA-UD3 AM3+
- RAM: 16GB (2x8GB) Corsair Vengeance Pro DDR3-2400 CAS11 @ DDR3-2133 CAS11
- GPU: Sapphire Tri-X Radeon R9 290X 4GB GDDR5
- SSD: Corsair Force LX 512GB SSD
- PSU: Corsair AX760i 760W
The FX-8350 unfortunately doesn’t allow for memory speeds higher than 2133MHz without tweaking the BClk, so we stuck with 2133MHz to prevent any memory bottlenecks. The motherboard choice might seem odd, but the GA-990FXA-UD3 has a staggering number of reviews on NewEgg and seems to be the weapon of choice for AMD enthusiasts on a budget. As it turns out, it’s a pretty nice board.
One of the benefits of going with an FX series CPU is that the motherboard ecosystem is very mature. While Intel’s X99 ecosystem still has a host of issues (many of them stemming from DDR4 compatibility), the 990FX is a fully known quantity. This board just works.
Our FX-8350 topped out at 4.7GHz and 1.475V on the core, and thermals were never an issue with the H100i. The FX-8350 boasts excellent heat transfer and while the heat threshold is substantially lower than on Intel’s chips, the FX-8350 just doesn’t run very hot.
The Adobe suite in PCMark 8 is a godsend for people involved in multimedia work, and the FX-8350 acquits itself well here. The FX-8350 gets a solid boost just bumping its core clock up to its turbo clock, and power consumption doesn’t increase appreciably. In fact, overclocking all the way to 4.7GHz offers a healthy performance boost without a serious increase in power demands.
Handbrake winds up being the worst case scenario for the FX-8350 because it flat out redlines the CPU. Peak power and average power are practically the same, and consumption increases by almost 100W. I’m keen to point out that an aggressive overclock on Devil’s Canyon can raise power consumption by as much as 70W or more, to say nothing of the nearly 200W overclocking Haswell-E can gain. Render times have an extremely steady decline as clock speeds increase, though. You can pretty much just pick a point on the curve you want to hit.
If the FX processors are bad gaming chips, that’s not presenting itself here. An increase of 700MHz nets maybe 1fps in BioShock Infinite, and Tomb Raider just plain doesn’t care. Power consumption does increase, but again, it’s modest.
When we take a look at how much average power consumption increases, we can see where the inflection point on this particular FX-8350 is: 4.4GHz. After that, it starts requiring substantial increases in Vcore to hit higher clocks. Up to that point, power consumption increases are pretty modest, though even after that, only Handbrake really gets in the thick of it. If you can stay under 1.4V on the core, you’re probably doing okay.
While chips like the FX-9590 and FX-9370 and their massive 220W TDPs don’t paint a rosy picture for AMD, mainstream workhorses like the FX-8350 catch kind of an unfair rap. The FX-8350 is a fine performer and overclocker, and power consumption isn’t horrifically higher than Intel hardware. Within the next couple of weeks we’ll be taking a look at what is arguably the mainstream star of AMD’s lineup, the FX-6300.