Ultimate AMD PC: what to buy and how to build it

Are AMD CPU's really the weak link we've been led to believe?

Reaching ground zero for the AMD argument

Bargain rig

Let's start at the beginning with the lowest of the low. If we can make an argument for building a rig based on the supposedly feeble four-core version of AMD's oft maligned FX processor, surely the job's a good 'un when we finally arrive at the four six- and eight-core processors?

Lest you have forgotten, four-core AMD FX processors are barely even that. The radical Bulldozer architecture sees a single processor module sharing several computing resources, including fetch and decode engines and the floating point execution unit. Okay, the integer units are doubled up. But four AMD FX cores aren't the same as four Intel cores. Or four of AMD's old Phenom II cores, for that matter.

If you were being really harsh, you could call an AMD module a glorified core with dual-thread capability and thus any AMD FX 4000 series chip is merely dual-core. Crikey.

What's more, the days of buying AMD processors and unlocking hidden cores in the motherboard BIOS are dead. It's not possible with FX chips. Then again, the FX 4170 model tested here is the quickest of the 4000 series and clocks in well above 4GHz.

As we know, not many games scale well beyond four threads, so maybe fewer cores but higher clocks makes sense. But what to pair it with?

This is our entry-level platform, which makes our chipset choice straightforward. AMD's basic 9 series effort, the 970, makes a lot of sense. It makes for an affordable motherboard but gives you the best chance of long-term compatibility and upgrades.

Since it's the latest generation chipset, critically it doesn't skimp on bandwidth. You get the latest 3.0 version of HyperTransport and SATA 6Gbps across the board. Yes, you'll miss out on a few frills, such as support for umpteen graphics cards in CrossFire multi-rendering mode. But where it matters, the 970 is more than adequate.

Next up is graphics. At this end of the market, the best bang for buck often comes from recently replaced cards from the previous generation. Similarly, the second-tier chip in any graphics family tends to be the most cost effective and, in turn, the second rung SKU of said GPU usually pumps the most pixels for the fewest pennies. Follow that philosophy to its logical conclusion and you end up with an AMD Radeon HD 6850.

And the net cost of all three of these core components? The FX 4170 is yours for just £93, 6850s can be had for about £85 and 970 boards start as £50. That's well under £250 for the complete package. Add memory, a PSU and maybe a 120-odd GB SSD (we'll assume you've some kind of Windows OS licence) and you can assemble the whole shebang for under £400. Pretty bloody compelling, eh?

But what about the reality? As we've already explained, the question here isn't whether you can pay more and get something faster. It's whether this platform is fast enough in isolation. And the simple answer is that most of the time in most games, this is a remarkably playable set up.

Of course, you can get just about any fairly recent PC running a game if you switch off enough of the eye candy. So our worry with this entry level rig was that we'd have to crush the details down horribly to achieve vaguely playable frame rates.

For the most part, that's simply not the case. Take Max Payne 3. With most of the details maxed out and both anti-aliasing and tessellation enabled at 1,920 x 1,080, the bargain basement solution pulls an average of 29 frames per second. Marginal? Yes. Playable? Just about.

Switch off anti-aliasing and you're looking at frames in the high 30s. Knock tessellation on the head (which frankly isn't all that dramatically implemented in Max Payne 3 much of the time) and you'll approach an average of 50 frames per second. That's nice, smooth gaming by any metric.

The choice is a little more stark with games like DiRT Showdown. Hit the Ultra switch and the combination of global illumination and busting out of the test card's 1GB frame buffer dragged the average frame rate at 1,920 x 1,080 down to just 16 frames per second. However, with the global details set to high and with anti-aliasing enabled, the result is a remarkable average of 56 frames per second.

And let's be honest. You'd struggle to pick the High setting from the Ultra setting in a blind test. They both look great.

The results in Just Cause 2 are even better. Crank pretty much everything to maximum and wind up the anti-aliasing to 4x and you'll still get 44 frames per second average. Nice.

If there's one game in our suite that gives us cause for a pause, it's Metro 2033. In many ways, it's the best-looking game in our test suite and it's certainly the most demanding. Choose the Very High global detail setting, enable 4x anti-aliasing and pump 1,920 x 1,080 pixels and the result is 17 frames per second. Yuck. Turning off the anti-aliasing doesn't help significantly, but step back from Very High to High and you will get an average of just under 30 frames per second and a gaming experience that's just about playable.

As for pure CPU performance, well, you're looking at getting roughly half the speed of a good Intel quad-core processor. The same goes, unsurprisingly, for an AMD FX processor in eight-core and four-module trim. But then it's always been clear that CPU performance is critical for things like video encoding.

The interesting question here, of course, is whether it's the graphics, the CPU or a bit of both holding back the performance when the gaming frame rates do drop a little.

Motherboard

Gigabyte GA-970A-UD3

Vital statistics
Price: £79
Manufacturer: Gigabyte
Web: http://uk.gigabyte.com
Socket: AM3+
Chipset: AMD 970 with SB950
Storage: 6x SATA 6Gbps USB 8x USB 2.0, 2x USB 3.0
Memory: DDR3 up to 1,866MHz
Graphics: 1x PCIe 2.0 x16

If it's the ultimate in bang for buck you seek, you'll struggle to beat a budget motherboard as you just get so much hardware for your money. Okay, there are cheaper boards based on the AMD 970 chipset, which is the entry level 9 Series effort.

Gigabyte's own 970A-DS3 can be had for a mere £70 or so. But we reckon the UD3 motherboard makes for a slightly better long-term proposition. For starters, you get better cooling for the chipset, the MOSFETs and all that.

Then there's better audio with 5.1 surround and optical-out. Moreover, it's not missing out on anything when it comes to the most important kit which determines raw bandwidth. That means six SATA 6Gbps ports and a pair of Etron USB 3.0 chips for a total of four USB 3.0 channels, double the number provided by the 970A-DS3.

Verdict: 4/5

Read the full Gigabyte 970A-UD3 review

Graphics card

XFX Radeon HD 6850

Vital statistics
Price: £86
Manufacturer: XFX
Web: www.xfxforce.com
Chipset: AMD Radeon HD 6850
Memory: 1GB GDDR
Memory: bus 256-bit
Core clock: 775MHz
Stream shaders: 960
Process technology: 40nm

At this end of the market, something's got to give. You can't have the very latest technology from the very biggest GPU combined with a ton of graphics memory. However, if you wind back the clock a little and go with something from the previous generation and the second tier of the product range, you still get an awful lot of graphics processor for under £100.

Take, for instance, the 960 DX11-capable stream shaders for starters. However, if there's any single statistic that confirms the HD 6850's status as a pukka pixel pumper, it's the meaty 256-bit memory bus. At high detail and resolutions, bandwidth is king.

It's a little ironic, therefore, that this board's greatest weakness is also memory related. At 1GB, it simply doesn't have enough of it.

Verdict: 2.5/5

Read the full XFX Radeon HD 6850 review

CPU

AMD FX 4170

Vital statistics
Price: £93
Manufacturer: AMD
Web: www.amd.com
Clockspeed: 4.2GHz, 4.3GHz
Turbo Cache: 4MB L2, 8MB L3 Socket AM3+
Process technology: 32nm
Memory: DDR3 up to 1,866MHz
TDP: 95W

If any CPU is going to make or break the theory that AMD's chips might be good enough after all, it's the FX 4170. With just two modules and four AMD-style CPU cores, it seems to be the worst of both worlds. By that we mean you suffer the poor per-thread throughput of the Bulldozer architecture and only have a couple of modules and a quartet of threads to make up for it. Run. Run for the hills!

Indeed, in traditional CPU tests like professional rendering or video encoding, the results are pretty predictable. The FX 4170 is slow. But what about games?

In most of our game tests pairing the 4170 with a Radeon HD 6850, performance is surprisingly good. What's more, where it does drop off, there's ample evidence that it's the 6850, not the FX 4170, holding things back.

Verdict: 3.5/5

Overall

Budget motherboards offer so much for your money and the Gigabyte GA-970A-UD3 is no exception and AMD's FX 4170 certainly isn't the weak link that you might expect. Instead, it's the Radeon HD 6850's measly 1GB of memory that's the problem.

Final verdict: 3/5