Does pure AMD make sense at the high end?

high-end rig

The core of the argument for AMD boils down to two notions. Firstly, there's the real-world experience - our 'good enough' concept of gaming performance. Then there's value for money. With that in mind, the notion of flinging significant quantities of folding cash at an AMD-only gaming rig doesn't seem like an immediate goer.

But everything's relative. An eight-core FX chip at around £120 is hardly breaking the bank. In fact, that won't buy you a quad-core Intel processor of any kind, much less an unlocked model or a Core i7 example with HyperThreading enabled. That's how yawning the price chasm between AMD and Intel has grown, and it plays directly to AMD's strengths.

Slightly more marginal is our AMD 990FX-based motherboard. It's Asus' Crosshair V Formula-Z specimen, and it retails in the region of £180. It's not the most expensive AMD motherboard in town. The Thunderbolt-enabled version of the same board, for instance, weighs in at a wallet-wilting £270.

But in the context of modern PCs, where so much of the performance-critical componentry resides inside the CPU package, including the northbridge and memory controller, you've got to be realistic about the implications of an expensive motherboard. It's not going to have a tangible impact on performance at stock clocks, even if you might get a little extra overclocking headroom.

More to the point, any money you spend on the motherboard isn't going into graphics, which is the most performance critical part of the gaming package. You could argue that's particularly critical at the high end, where the incremental price gaps between graphics chipsets open into spectacular canyons. Thus, examples of AMD's Radeon HD 7970 kick off at around £300, while you can snag an HD 7950 for just £220.

In pure hardware terms, there really isn't a lot to justify that. The stream shader count drops from 2,048 to 1,792 and the texture units shrink from 128 to 112, but that's it. You get all 32 ROPs, a 384-bit memory bus and 3GB of speedy GDDR5 graphics memory.

Things get a little more complicated when it comes to clockspeeds, especially since AMD rolled out not only 7950s and 7970s with higher frequencies, but also 'boost clock' automatic overclocking feature. It's not always obvious what you're getting, so inspect the specs with care. That said, the real-world difference isn't very dramatic whichever version you go for, making the 7950 the obvious choice, boosted or otherwise.

Anyway, the overall impact of hooking up the FX 8120 CPU, Asus 990FX board and 7950 graphics is pretty impressive. Finally, we've achieved an it-just-works solution courtesy of all-AMD components.

In our benchmarks, the results were the same whatever the game, whatever the setting: smooth, slick and enjoyable gaming. Now, you might view that as a given with this class of components. After all, we're talking about a combined price of over £500 for CPU, motherboard and graphics. That's before you add other essentials like memory, storage, a power supply, a case and a Windows license.

But try this for size. You can't say the same of Intel's Core i5-3570K teamed with a Z77 motherboard and Nvidia's GeForce GTX 670. In some of our benchmarks, there's little to nothing in it.

Max Payne 3 at 1,920 x 1,080 at maximum detail with both tessellation and anti-aliasing enabled? It's 45 frames per second for end-to-end AMD, and 44 for Intel and Nvidia. It's the same spiel for Metro 2033, with AMD pipping the evil Intel-Nvidia alliance 33 to 31 at maximum detail.

Okay, the opposition scores a clear win in Just Cause 2, racking up a mighty 103 frames per second to AMD's mere 89. But again, it's an academic victory; 89 frames per second is plenty quick enough.

However, there is one game where a tangible gap appears - a frame rate differential you can actually feel. And guess what? It falls in AMD's favour. We speak, of course, of DiRT Showdown with that pesky global illumination option enabled. It's a killer for the Intel-Nvidia combo, dragging average frame rates down to 18. Knock the settings back from Ultra to High, disabling global illumination in the process, and performance leaps to 94 frames per second. And the AMD platform? You get a healthy 43 frames per second in Ultra mode with global illumination on, and a modest jump to 63 if you scale back to High and knock global illumination on the head.

To be clear, this isn't Intel's fault. You could pair the Core i5-3570K with an AMD graphics chip and sidestep the issue. In fact, you'll get better results with the Core i5 and a Radeon HD 7870, much less stretching all the way to a 7950. But the overall result doesn't square with the received wisdom. You'd expect the AMD rig to be the one that drops the ball.

As for more general system performance, the extra threadability of the eight-core FX processor in this top-end AMD solution closes much of the gap to that pricey Intel chip. A score of 4.98 points plays 6.01 in Cinebench, and it's 31 frames per second to 34 in x264 HD video encoding. Intel remains clearly quicker, but at a price.

So, there you have it. Even when scaling up the price lists, you can still make an argument for AMD. Don't get us wrong. We're not suddenly suggesting you fling that Intel CPU or Nvidia graphics card out the window. Intel CPUs remain the quickest, and Nvidia's GPUs are far from fatally flawed.

But the AMD alternative is remarkably realistic. Actually, it's more than just realistic. It's competitive at worst and superior at best, and offers more consistent worst-case scenario performance. Remarkable.

Motherboard

Asus Crosshair-V Formula-Z

Vital statistics
Price: £180
Manufacturer: Asus
Web: http://uk.asus.com
Socket: AM3+
Chipset: AMD 990FX with SB950
Storage: 7x SATA 6Gbps USB 8x USB 2.0, 4x USB 3.0
Memory: DDR3 up to 1,866MHz
Graphics: 2x PCIE 2.0 x16, 1x PCIE 2.0 8x

If there was a single component we were most dubious about coming into this AMD-gasm, it involved the notion of a high-end motherboard for AMD processors. Surely the extra money is better spent on the CPU and graphics?

The simple answer is yes. The more nuanced response goes something like this: many of the extra features involve functionality few of use are likely to use, like support for triple-card graphics action. We're not huge fans of multi-GPU at the best of times, but support for two cards, as per MSI's 990X board, is certainly sufficient.

On the other hand you get a very nice physical object that will extract the maximum in terms of overclocking, and also offers maximum bandwidth with seven SATA 6Gbps ports and four USB 3.0 sockets. That's nice, but it's not £100 nice.

Verdict: 3.5/5

Graphics card

AMD Radeon HD 7950

Vital statistics
Price: £220
Manufacturer: AMD
Web: www.amd.com
Chipset: AMD Radeon HD 7950
Memory: 3GB GDDR
Memory bus: 384-bit
Core clock: 850MHz (925MHz Boost)
Stream shaders: 1,792
Process technology: 28nm

The cut-down version of the incumbent title-holder of world's most powerful graphics chip. That's often the sweet spot when it comes to balancing price, performance, and that most elusive of technological virtues, longevity.

But with value so central to the AMD, is a Radeon HD 7950 a bit of an over-reach? More to the point, can AMD's CPUs keep up?

Funnily enough, yes. AMD FX 8120 plus Radeon HD 7950 makes for a surprisingly effective and consistent package. Certainly it helps that the Radeon HD 7950 has plummeted in price since launch late last year. At over £300, it wasn't very attractive, but at nearer £200 and with some recent fettling in terms of frequencies, it's suddenly quite compelling. This all-AMD idea really is working out rather well.

Verdict: 4.5/5

CPU

AMD FX 8120

Vital statistics
Price: £120
Manufacturer: AMD
Web: www.amd.com
Clockspeed: 3.1GHz, 4.0GHz
Turbo Cache: 8MB L2, 8MB L3
Socket: AM3+
Process technology: 32nm
Memory: DDR3 up to 1,866MHz
TDP: 125W

Save for the slightly quicker-clocked 8150 chip, this is as good as it currently gets with AMD processors - and it's yours for just £120. That can't be a good thing for AMD's margins and profitability, but that's not your problem.

Instead, you want to know whether there's any benefi t to having the full four Bulldozer modules and eight AMD-style cores. On balance, we'd say yes. There's only £28 between the 8120 and the two-module, four-core 4170, so you're getting twice the hardware for a lot less than twice the price.

Okay, 8120 clocks are significantly slower, especially when running multi-threaded code. But as an overall compromise taking into account non-gaming performance too, it's the chip we'd choose. And that really isn't what we expected before we dived into this AMD-reassessment endeavour.

Verdict: 4.5/5

Overall

Proof positive that an all-AMD solution can cut it with modern games. Sometimes it even out-performs the competition. A properly slick gaming platform, but the motherboard is too pricey.

Verdict: 4.5/5