AMD Kaveri review
AMD’s APUs – “accelerated processing units” – combine CPU and GPU silicon on a single die to provide cost-effective all-round computing. Its new “Kaveri” chips update last year’s Richland models with AMD’s new 28mm Steamroller CPU core, and a new GPU based on AMD’s GCN architecture. They also introduce the new socket FM2+ – so be aware that you can’t drop a Kaveri chip into a Trinity or Richland board.
Kaveri clock speeds are more modest than in the previous generation. The flagship Richland A10-6800K had a stock speed of 4.1GHz, dynamically clocking up to 4.4GHz as needed, plus a Radeon-branded GPU running at 844MHz. The new top-end A10-7850K dials that back to 3.7GHz, with Turbo speeds up to 4GHz; the GPU is clocked at 720MHz. The A10-7700K and A8-7600 models offer even more restrained frequencies, and GPUs with reduced shader counts.
These reduced speeds are offset by architectural improvements. AMD has claimed that Steamroller can execute up to 20% more instructions per clock cycle than its predecessor (the “enhanced Piledriver” core used by Richland). The Radeon R7 GPU meanwhile is designed not only for playing games, but also to accelerate application performance in software optimised for DirectCompute and OpenCL.
In regular desktop applications, however, we saw little benefit from these changes. We tested the A10-7850K and the A8-7600 under Windows 8.1, running with 8GB of RAM (of which 1GB was reserved for the GPU) and a 120GB Kingston SSDNow V300, connected to an Asus A88XM-A motherboard.
The A10 came out slightly slower than last year’s A10-6800K, with an overall score of 0.73 versus the older chip’s 0.81. Some of this can be attributed to our having tested the older chip under Windows 7, which is typically a few percentage points faster than the more recent OS, but it’s still not a performance to be proud of. Intel’s comparably-priced Core i5-4440 achieved an overall score of 0.93 in the same test.
More impressive was the A8 model, which despite its much lower price ranked only a fraction behind the A10 with an overall score of 0.72. In our gaming test too, we saw the A8 almost match its its much pricier brother: the pair achieved 43fps and 44fps respectively in our Medium quality Crysis test. For comparison, Intel’s Core i5-4440 mustered only 34fps in our Medium quality Crysis test.
Since the hardware is brand new, updated drivers could yet boost these benchmark scores. And for gamers, The “K” suffix on AMD’s high-end models also indicates the possibility of overclocking these chips to push performance higher.
If power consumption is more of a concern, an interesting technical feature introduced by Kaveri is user-configurable TDP, which lets you manually switch the chip’s energy-management thresholds, perhaps to suit a compact case with limited cooling, or simply to save power. It needs BIOS support, however, and our test system hadn’t yet received the necessary update. At the default 95W TDP, total power draw while sitting idle was a very reasonable 35W, rising to 145W under 100% CPU load.
Other features in Kaveri include full support for 4K video playback at 60Hz, with dynamic upscaling of HD media. To partner these video-processing capabilities, the design also introduces new TrueAudio processing, which promises to enhance the directionality of sound and clean up background noise.
A worthy upgrade?
The A10-7850K may offer advantages for GPU computing, but in everyday applications we found performance doesn’t quite measure up – not against Intel’s Core i5, and not against the older Richland A10-6800K, which is still on sale at a lower price. That makes Kaveri as a whole difficult to recommend right now.
With an expected retail price of £90, however, the A8 stands out as an attractive choice for system builders on a budget, and for gamers in particular. There’s more power here than the model number might suggest, and when it comes to 3D gaming, it comfortably outpaces more expensive Intel hardware.
|Cores (number of)||4|
|L2 cache size (total)||4.0MB|
|Thermal design power||45-95W|