AMD A8-3850 review

AMD’s new processor architecture, codenamed ‘Llano’ combines both processing and graphics hardware on one chip – making what AMD calls an Accelerated Processing Unit, or APU. We’ve already tested the mobile platform in a prototype laptop, and found that while it couldn’t compete with Intel’s Sandy Bridge processors in 2D applications, 3D performance was streets ahead.

Desktop processors based on the new Llano architecture have the codename ‘Lynx’, and there are four models: the A6-3600, A6-3650, A8-3650 and A8-3850. Each of these APUs has four ‘Stars’ cores, which are upgraded versions of the K10 cores found in AMD’s Phenom II processors. The Stars cores are based on a 35nm rather than 45nm process, which results in a lower Thermal Design Power (TDP) – while the K10-based Phenom II X4 processors have TDPs of 95W for the slower models and 125W for the Phenom II 955 and up, the new A-series processors have TDPs of 65W for the slower A6-3600 and A8-3800 processors and 100W for the A6-3650 and A8-3850. This means they run cooler than the old chips, and AMD recommends using standard Socket AM2 or AM3 processor coolers. The new chips do, however, require a new socket, called FM1 – see our review of the FM1-equipped Asrock A75 Pro4.

Unusually for AMD, a new processor means a new socket type

Both the A6 and A8 processors have four cores and 4MB of L2 cache, but the main differences are in the graphics. The A6 chips have 320 stream processors and a 443MHz core, while the A8s have 400 stream processors and a core running at 600MHz. Our test A8-3850 showed itself to be far more capable than our reference Intel Core i5-2500K in games. While the A8-3850 couldn’t run our new Dirt 3 benchmark at our high-end settings of 1920×1080 with 4xAA and Ultra detail, once we ran it at our ‘low’ settings (1,280×720, 4xAA, High detail) we saw a smooth 35fps. Intel’s Core i5-2500K could only manage around 13fps in the same test.

The chipset has another gaming ace up its sleeve. If you pair an A-series processor with an AMD 6-series graphics card, you can run the two in CrossFire mode for a performance boost. On its own, a bottom-of-the-range £42 512MB AMD Radeon HD 6450 managed 28.6fps in Dirt 3 at our low settings, which is playable, but only just. Once we turned on CrossFire, the frame rate almost doubled to a silky-smooth 52.3fps. The game even ran at 1,920×1,080 and High detail at a smooth 34.2fps once we turned off anti-aliasing. While this combination isn’t as quick as a more powerful card on its own, such as the £75 1GB Radeon HD 6670, which managed 47.2fps at 1,920×1,080, High detail and no AA, it’s a fine way to add performance to a Llano processor-based system for a minimal outlay.