PC Gamer - October 2011

TESTED
A8;3850

AMD

The A8-3850 processor is the culmination of AMD’s long- simmering Fusion architecture. AMD blended a quad-core CPU build (similar to existing Phenom offerings) and poured in some Radeon GPU goodness to create what the company calls an APU (Advanced Processing Unit). The integrated GPU is the most ambitious graphics core built onto a CPU chip yet, stuffing a full-on, low-end DX11 graphics engine onto the processor. AMD’s hoping the more advanced GPU inside the A8-3850 will make up for the somewhat anemic performance of their traditional CPU cores.

Unfortunately, AMD’s also breaking with tradition in a not-so-good way: the APU procs require a completely new socket (dubbed FM1), so if you want one, get ready for a forced mobo upgrade. Along with the new CPU, AMD’s shipping an updated Southbridge chip (a

The new APU procs still have those fragile-as-hell pins. Be extra-careful handling!

shader cores running at 600MHz plus 20 texture units. Sadly though, compared to the Radeon HD 6770 (which got a not-so-hot 68% last issue), this is half the number of shader cores and a 250MHz lower clock. Ouch.

It requires a completely new socket, so get ready for a mobo upgrade.

mobo’s Southbridge controls areas such as USB and the BIOS), dubbed the Fusion Controller Hub (or FCH). The higher-end A75 version of the FCH is the first PC core logic to implement USB 3.0 and SATA 6Gbps on a single chip. Pretty cool.

But it’s the A8 that’s the most interesting: the CPU itself consists of four traditional Phenom-style cores running at 2.9GHz. The graphics engine built onto the A8-3850 runs in parallel with all those cores. The integrated GPU consists of 400

It’s a Radeon,
the driver says so!

AMD calls the A8’s GPU a Radeon HD 6550D, but don’t be fooled by the naming scheme: it’s not directly comparable to a standard Radeon videocard due to the need to share memory with the CPU. And when memory sharing by two ordinarily separate parts is required, you’re probably gonna see a performance hit in both components— which was unfortunately verified in my tests. In fact, I couldn’t get the Shogun 2 benchmark to finish at all running at 1920x1080. The numbers in DiRT 3 and Metro 2033 were OK for low-end hardware, but certainly not jaw-dropping.

However, if 14fps in Metro 2033 at low
detail isn’t exactly awesome sounding, you
can always add an entry-level graphics card
for $120 or less, such as the Radeon HD
6670. The two GPUs then take advantage
of AMD’s CrossFireX technology,
improving framerates, and
allowing you to bump up the eye-
candy. In fact, when you install a second
low-end graphics card, AMD’s Catalyst
software sees the pair as a single Radeon
HD GPU. The HD 6670 plus the inte-
grated GPU becomes the Radeon HD
6690D2, for example. Of course, not all
games take advantage of CrossFireX, but
most current-generation games will see a
performance boost that’s almost doubled.