In many ways, AMD’s FX processor series seems to have fallen by the wayside lately. While A-series APUs were refreshed with new Kaveri silicon this past January, the FX family has been trucking along with the same Vishera silicon since 2012. The accompanying 990FX chipset is a year older and begging for a replacement. At this point, one might have expected AMD to let the FX family die a dignified death—then fill in the gaps with high-octane Kaveri APUs.

But that’s not what the company did.

Instead, AMD has just shaken up the FX series with a trio of new models. The additions are based on the same Vishera silicon as before, but the magic of binning has yielded a faster 125W top-of-the-line part as well as two eight-core offerings with 95W thermal envelopes. One of them, the FX-8370E, will be the subject of our review this morning.

Today’s shakeup also involves a round of price cuts, the biggest one of which will send the family’s 220W flagship, the FX-9590, into the same waters as Intel’s Core i5-4690K. Other price cuts apply to the FX-9370 and FX-8320, which are both getting a tad cheaper.

Put together, these are without a doubt the biggest changes AMD’s FX line has seen in well over a year. Let’s look at them one by one before we fire off our benchmarks.

When it came out in June 2013, the FX-9590 could be found only inside select pre-built PCs from system integrators. It took a couple of months for the chip to hit e-tail listings, where it initially sold for a daunting $880. By October 2013, the FX-9590 had fallen to $350; and just prior to today’s price cut, Newegg had it on sale for $299.99.

As of today, the FX-9590 should be available at e-tail for only $229.99. This price pits the FX flagship against Intel’s cheapest Devil’s Canyon processor, the Core i5-4690K, which is available for $239.99. The Core i5 admittedly consumes a fraction of the power, at 88W, and comes with a bundled heatsink and fan, which the FX-9590 does not. (AMD offers a version of the FX-9590 with a liquid cooler in the box, but that kit will set you back $290 after these cuts come into effect.) Still, the FX-9590 is in a more competitive position now than ever.

For users intimidated by the FX-9590’s 220W power envelope, AMD has introduced the FX-8370, its fastest 125W processor yet. Aside from a 100MHz increase in peak Turbo headroom, the FX-8370 has basically the same specs as the FX-8350. Since the new model is $20 more expensive, some may be tempted simply to buy the slower, cheaper chip and overclock it. All members of the FX series, past and present, still have fully unlocked upper multipliers. The FX-8370 is AMD’s first new top-of-the-line FX-8000-series processor since October 2012, though, which has got to count for something.

The most interesting additions to the lineup are these FX “E” chips. They offer up the same eight-core recipe as the aforementioned 125W parts, but in a more reasonable 95W power envelope.

95W FX processors with eight cores have been available before, but these days, the only ones still around are four- and six-core parts. AMD says it intends the “E” chips to serve as upgrades to those models inside systems that “don’t really have the infrastructure” to support a 125W CPU. Simply put, someone with a quad-core FX chip could replace it with an FX-8370E and enjoy a sizeable performance boost without needing a new motherboard, cooler, or power supply. Not even a BIOS update would be necessary, apparently. AMD says “lots” of its users have requested an upgrade path like this, and it was happy to oblige.

In new builds, the “E” chips will vie for supremacy with Core i3 and i5 processors from Intel’s Haswell Refresh series. AMD mentioned the Core i5-4430 and i5-4460 as likely competitors, but the FX-8370E’s most direct opponent will probably be the i5-4590, which carries the same $199.99 asking price at e-tail.

Model Modules/ threads Base clock (GHz) Max Turbo clock (GHz) Max DDR3 speed (MT/s) L3 cache (MB) TDP (W) Old price (Newegg) New price (SEP) FX-9590 4/8 4.7 5.0 2133 8 220 $299.99 $229.99 FX-9370 4/8 4.4 4.7 2133 8 220 $219.99 $210.99 FX-8370 4/8 4.0 4.3 1866 8 125 – $199.99 FX-8350 4/8 4.0 4.2 1866 8 125 $179.99 $179.99 FX-8320 4/8 3.5 4.0 1866 8 125 $159.99 $146.99 FX-8370E 4/8 3.3 4.3 1866 8 95 – $199.99 FX-8320E 4/8 3.2 4.0 1866 8 95 – $146.99

Here’s a full list of specs and prices for the updated FX lineup. “Old” prices were grabbed from Newegg this past weekend, while new prices are the suggested e-tail figures given to us by AMD.

As you can see, AMD has reduced base clock speeds quite a bit to give the “E” chips their lower TDPs. The Turbo Core peaks are the same as for the non-E models, however.

The FX-8370E, for example, can clock itself as high as the FX-8370 via Turbo. That means it has the potential to be a very strong performer in the lightly threaded workloads that dominate day-to-day PC use—all the while sipping less power than a 125W CPU. The FX-8370E’s lower base speed will probably hinder it in heavily multithreaded tasks, but thanks to its eight hardware threads, it may still put up a decent fight against Intel’s quad-core offerings.

That’s the theory, anyhow. AMD sent us an FX-8370E to test, and we put it through our suite to see if the theory matches the reality. Keep reading for the results.

Our testing methods

As usual, we ran each test at least three times and have reported the median result. Our test systems were configured like so:

Processor AMD FX-8350 AMD FX-8370 AMD A6-7400K Pentium G3258 AMD A10-7800 Core i3-4360 Core i5-4590 Core i7-4790K Motherboard Asus Crosshair V Formula Asus A88X-PRO Asus Z97-A North bridge 990FX A88X FCH Z97 Express South bridge SB950 Memory size 16 GB (2 DIMMs) 16 GB (4 DIMMs) 16 GB (2 DIMMs) Memory type AMD Performance Series DDR3 SDRAM AMD Radeon Memory Gamer Series DDR3 SDRAM Corsair Vengeance Pro DDR3 SDRAM Memory speed 1866 MT/s 1866 MT/s 1333 MT/s 2133 MT/s 1600 MT/s Memory timings 9-10-9-27 1T 10-11-11-30 1T 8-8-8-20 1T 10-11-11-30 1T 9-9-9-24 1T Chipset drivers AMD chipset 13.12 AMD chipset 13.12 INF update 10.0.14 iRST 13.0.3.1001 Audio Integrated SB950/ALC889 with Realtek 6.0.1.7233 drivers Integrated A85/ALC892 with Realtek 6.0.1.7233 drivers Integrated Z97/ALC892 with Realtek 6.0.1.7233 drivers OpenCL ICD AMD APP 1526.3 AMD APP 1526.3 AMD APP 1526.3 IGP drivers – Catalyst 14.6 beta 10.18.10.3652

Processor Core i5-2500K Core i7-4960X Core i7-5960X Motherboard Asus P8Z77-V Pro Asus P9X79 Deluxe Asus X99 Deluxe North bridge Z77 Express X79 Express X99 South bridge Memory size 16 GB (2 DIMMs) 16 GB (4 DIMMs) 16 GB (4 DIMMs) Memory type Corsair Vengeance Pro DDR3 SDRAM Corsair Vengeance DDR3 SDRAM Corsair Vengeance LPX DDR4 SDRAM Memory speed 1333 MT/s 1866 MT/s 2133 MT/s Memory timings 8-8-8-20 1T 9-10-9-27 1T 15-15-15-36 1T Chipset drivers INF update 10.0.14 iRST 13.0.3.1001 INF update 10.0.14 iRST 13.0.3.1001 INF update 10.0.17 iRST 13.1.0.1058 Audio Integrated Z77/ALC892 with Realtek 6.0.1.7233 drivers Integrated X79/ALC898 with Realtek 6.0.1.7233 drivers Integrated X99/ALC1150 with Realtek 6.0.1.7233 drivers OpenCL ICD AMD APP 1526.3 AMD APP 1526.3 AMD APP 1526.3 IGP drivers – – –

They all shared the following common elements:

Hard drive Kingston HyperX SH103S3 240GB SSD Discrete graphics XFX Radeon HD 7950 Double Dissipation 3GB with Catalyst 14.6 beta drivers OS Windows 8.1 Pro Power supply Corsair AX650

Thanks to Corsair, XFX, Kingston, MSI, Asus, Gigabyte, Cooler Master, Intel, and AMD for helping to outfit our test rigs with some of the finest hardware available. Thanks to Intel and AMD for providing the processors, as well, of course.

Some further notes on our testing methods:

The test systems’ Windows desktops were set at 1920×1080 in 32-bit color. Vertical refresh sync (vsync) was disabled in the graphics driver control panel.

We used a Yokogawa WT210 digital power meter to capture power use over a span of time. The meter reads power use at the wall socket, so it incorporates power use from the entire system—the CPU, motherboard, memory, graphics solution, hard drives, and anything else plugged into the power supply unit. (The monitor was plugged into a separate outlet.) We measured how each of our test systems used power across a set time period, during which time we encoded a video with x264.

After consulting with our readers, we’ve decided to enable Windows’ “Balanced” power profile for the bulk of our desktop processor tests, which means power-saving features like SpeedStep and Cool’n’Quiet are operating. (In the past, we only enabled these features for power consumption testing.) Our spot checks demonstrated to us that, typically, there’s no performance penalty for enabling these features on today’s CPUs. If there is a real-world penalty to enabling these features, well, we think that’s worthy of inclusion in our measurements, since the vast majority of desktop processors these days will spend their lives with these features enabled.

The tests and methods we employ are usually publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Power consumption and efficiency

The workload for this test is encoding a video with x264, based on a command ripped straight from the x264 benchmark you’ll see later.





Lower TDP or not, the FX-8370E doesn’t draw any less power than its 125W cousins at idle. The Core i5-4590 consumes 19W less here.

Fire up a video-encoding workload, and the FX-8370E shines compared to its relatives. While its TDP is only 30W lower than the FX-8370’s on paper, the FX-8370E actually draws almost 50W less in this test. Too bad that difference isn’t enough to close the gap with the Core i5-4590.

We can quantify efficiency by looking at the amount of power used, in kilojoules, during the entirety of our test period, when the chips are busy and at idle.

Perhaps our best measure of CPU power efficiency is task energy: the amount of energy used while encoding our video. This measure rewards CPUs for finishing the job sooner, but it doesn’t account for power draw at idle.

As we’ll see in our performance section, the FX chips chew through this x264 test quite a bit slower than the Intel ones. That means the AMD CPUs spend more time at peak power draw, which compounds the effect of their already-high power consumption. No wonder they’re stuck at the bottom of the graph. The FX-8370E isn’t the worst of the bunch, but it’s still much less efficient than the Core i5-4590.

Discrete GPU gaming

The FX-8370 is absent from these performance tests, since we didn’t have time to benchmark it fully. Sorry about that. We’ve been exceptionally busy around here these past few days, as you’ve probably noticed.

Anyhow, in Thief with the Direct3D renderer enabled, the FX-8370E trails the FX-8350 by a small margin—and the Intel pack by a larger one. This game suffers more from the FX-8370E’s lower base clock than it benefits from the chip’s higher Turbo peak, apparently.

AMD’s Mantle API does a pretty solid job of cutting CPU overhead. Enable it in Thief, and the margin between the FX-8370E and the other contenders shrinks to almost nothing. Results like these may become the norm after DirectX 12 arrives late next year. For now, though, they’re the exception.

(If you’re wondering why the dual-core CPU results are missing from the graph above, it’s because the game wouldn’t start in Mantle mode with those chips. Weird.)

Productivity

Let’s run through a quick sampling of some desktop-style applications that rely on the CPU cores to do their work.

In these apps, which all put multiple threads to work, the FX-8370E is slower than the FX-8350 across the board. That’s pretty much what we expected, since the FX-8370E has a lower base speed, and it probably doesn’t hit its Turbo peak with all eight cores sweating away.

Still, the FX-8370E’s multithreaded performance is enough to close the gap with the Core i5-4590 in a couple of tests. The two chips are closely matched in Handbrake and GCC, and the Core i5 actually falls behind in 7-Zip.

LuxMark OpenCL rendering

LuxMark is a nice example of GPU-accelerated computing. Because it uses the OpenCL interface to access computing power, it can take advantage of graphics processors, CPU cores, and the latest instruction set extensions for both. Let’s see how quickly this application can render a scene using a host of different computing resources.

Here, LuxMark is running on the CPU alone, unaided by discrete or integrated graphics. The FX-8370E falls behind the FX-8350 again, but it edges out the i5-4590.

This is what happens when we run LuxMark on just our discrete GPU. Unsurprisingly, a faster processor doesn’t make much of a difference. The FX processors hold back the discrete Radeon a tad more than the rest, but only just a tad.

In this last test, the CPU and discrete GPU team up to do the work as quickly as the system can manage. The FX-8370E outruns the i5-4590 by just a hair here, and it’s nearly as fast as the FX-8350.

Cinebench rendering

Cinebench also renders a 3D scene, but it uses only CPU power to do so.

The FX-8370 returns for a brief encore here, since Cinebench gives us an important look at single-threaded vs. multithreaded performance.

Cinebench confirms the hypothesis we outlined earlier: in a single-threaded workload, the FX-8370E’s high Turbo speed allows it to perform just as well as its 125W counterpart—and better than the FX-8350. Is that enough to catch up with Intel? Well, no. Even the $70 Pentium G3258 has better single-threaded performance than the FX-8370E.

In our multithreaded test, however, the FX-8370E’s extra threads allow it to edge out the Core i5-4590—despite falling behind the FX-8370 and FX-8350 because of its lower base speed.

Conclusions

Let’s wrap things up with one of our famous price vs. performance scatter plots.

We used AMD’s suggested e-tail prices for the FX series and Newegg prices for the rest. On the performance front, we used geometric mean of results from our full test suite—the same one featured in our review of Intel’s Core i7-5960X processor. We presented an abridged version of that suite on the previous pages of this article, but we used our full slate of numbers for our value calculation.

The FX-8370E caught up with the Core i5-4590 in a handful of our tests, but it doesn’t quite measure up overall. In pure performance terms, the $180 FX-8350 is more of a match for Intel’s $200 quad-core CPU.

Now, the figures above don’t account for power efficiency. The FX-8370E is a better buy than the FX-8350 if you’re all about staving off arctic thawing, or if you’re upgrading a system that’s not equipped to handle a 125W processor. As we saw on page three, however, the reduction from 125W to 95W isn’t enough to close the gap with Intel. The Core i5-4590 is much more power-efficient than the FX-8370E across the board.

That makes the FX-8370E a tough sell for a new PC build. This chip does have an unlocked upper multiplier, which gives it an advantage of sorts over the Core i5. However, overclocking will only worsen the already poor power-efficiency picture—and folks who don’t care about power efficiency should be buying the FX-8350.

Then there’s the accompanying platform. AMD’s 990FX chipset, which still powers high-end Socket AM3+ motherboards, came out in May 2011. It lacks native support for PCI Express 3.0, SATA Express, M.2, and even USB 3.0. ASRock managed to jerry-rig an M.2 slot onto its Fatal1ty 990FX Killer mobo, but that slot is limited to PCIe Gen2 speeds, and the board itself costs a hefty $169.99. Over in the Intel aisle, you can find an Asus board based on Intel’s brand-new Z97 chipset with a Gen3 M.2 slot for 40 bucks less.

So, yeah. If AMD really wants to shake up the FX series, it ought to introduce new silicon based on the Steamroller cores that drive Kaveri, and it ought to offer a new chipset worthy of the FX’s enthusiast aspirations. Price cuts and variations on old themes are all well and good, but they’re not enough if AMD wants to keep up with the blue team.