AMD A8-3870K Black Edition APU £120

25th Jan 2012 | 16:15

AMD A8-3870K Black Edition APU

The makings of a low-cost gaming media centre

TechRadar rating:

4 stars


Asymmetric Crossfire;Decent onboard graphics for 720p, almost 1080p friendly


Old architecture;Core i3 still faster with discrete GPU


Not to be outdone by new graphics releases AMD is going back to the APU drawing board with the new AMD A8-3870K processor.

While its flagship FX processors are failing to shine it does seem a little on unfair on AMD that at the other end of the market it has a chip which really ought be cleaning up.

Its Llano Fusion APUs, which combine a multi-core CPU and a Radeon graphics part on one die, are actually rather good.

They may be based on an older processor architecture, but quad core examples like this A8-3870 hold their own against Intel's similarly priced dual core Core i3s in CPU benchmarks.

When it comes to 3D tasks like gaming, the on board HD6550D is simply in a different league to Intel's laggardly HD Graphics 3000 cores.

AMD a8-3870k

How could they get better? We'd like a chunky price drop, but that's not going to happen.

Instead, AMD has introduced 'Black Editions' of the chips, recognisable by their 'K' suffix. Just like Intel chips with a K moniker, they come with an unlocked multiplier which makes them more suitable for overclocking.

Now, you might think that anyone who wants to overclock a chip will be looking at something a little more high-end than these very basic processors, but the entire raison d'etre for overclocking is to turn something cheap into an unexpected powerhouse.

An unlocked, gaming-capable hybrid chip for just over £100 sounds like the stuff hardware hackers' dreams are made of. But does it deliver on that promise?


As expected, even with a 100MHz increase over the older AMD A8-3850, at stock speeds the A8-3870K doesn't distinguish itself fully against the Core i3.

Put the two chips head to head solus and it has the edge, but if you're using external graphics the Core i3 still pulls away in any game that's not massively multithreaded (Shogun 2, tellingly, is).

And what of the overclocking? It's actually a bit disappointing really. At the speeds we achieved using fairly basic equipment, the difference is often not enough to be worth even trying.

DirectX 11 gaming performance

AMD a8-3870k benchmarks

DirectX 11 tessellation performance

AMD a8-3870k benchmarks

CPU rendering performance

AMD a8-3870k benchmarks

CPU video encode performance

AMD a8-3870k benchmarks


A stock A8-3870K ships with its CPU set at 3GHz and the graphics core clocked at 800MHz. Our attempts to increase these weren't exactly stellar - it ramped straight up to 3.4GHz/800MHz, but any attempts to go further were unstable enough to be frustrating.

With more fine-tuning and a really good cooler, we've seen reports of much higher clockspeeds, but we're not overly sure it's ultimately worth it for the performance returns.

Plus, it's unlikely that motherboard manufacturers are going to get behind this platform with high end boards full of good, stable overclocking features – because potential purchasers just aren't going to spend the extra they'll cost to make.

AMD a8-3870k

Still, since the A8-3870K is already available for less than its non-tweakable predecessor, the A8-3850, the unlocked multiplier is more of a pleasant extra to have.

So even if our dream of using one to outperform a Core i7 isn't going to happen, the A8-3870K is still a great little chip.

The CPU part of Llano was never in much doubt. Based on the same architecture as Athlon II and Phenom II with a die shrink, it's old but still capable.

Because it has four native cores it outperforms Core i3 in tasks like media rendering and so on, although Intel's computational engine is still superior in games – even if its graphics lags far behind.

For a workplace PC, then, the A8-3870K is an exceptional choice. It'll beat a similarly priced Core i3 system at everything.

It gets a bit more complicated if you're after a budget system that can game at 1080p – to use as a media centre, for example.

Even overclocked, the A8-3870K alone isn't an alternative to discrete graphics – although it does come very close if you're willing to sacrifice graphics quality. Battlefield 3, for example, is this far off being playable at 1920x1080 with low image quality settings.

Which are still bloody good looking.

Skyrim at similar settings runs like a dream.

If you're thinking of adding in a mid-range card like the HD 6870 or even something as powerful as an Nvidia GeForce GTX 560Ti, though, Intel just wins through – although it's a draw in CPU limited games like Shogun 2 and Skyrim.

AMD's architecture does have the curious disadvantage of performing slower in CPU benchmarks when discrete graphics are attached too.

But that leaves one feature that we haven't discussed yet which bring us down in AMD's favour.

That feature is Asymetrical Crossfire – the ability to use both the A8-3870K's graphics and a low power GPU, such as an AMD HD 6670, for a gaming experience that's capable of playing most games at 1080p with medium settings.

That's a hell of a thing in AMD's favour.

Enough that while it's not going to be our chip of choice for a workstation or enthusiast games rig, if you want a small, low cost PC which is capable of occasional games at console quality, it's a steal.

We liked

Where it comes into its own is as a flexible platform for a quad core office machine or a flexible and capable gamer with Asymmetric Crossfire.

We disliked

The potential to overclock is a bonus, but really not enough by itself to make us favour this chip over any other quad core Llano.

Final word

Not the budget buster we hoped for, but further's our faith in AMD to make Fusion the low cost platform of choice.

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