Review: The new xXx HD6950 is xXx-tra cool, but also a little too xXx-pensive. Also, easy to make jokes about...
AMD has achieved more than just a name change coming from the 68xx range of cards. The 69xx series introduced a new microarchitecture known as the Cayman core; one which represents the most significant change since the seemingly ancient HD2900. Cayman was intended to be a 32nm part, however TSMC decided to drop 32nm for work on the upcoming (and more economically viable) 28nm project. This resulted in a larger part, with sacrifices being made to prevent a Fermi-esque monster die. This included a reduction in SIMDs and the lack of a PCIe 3.0 controller, the latter being of little importance in hindsight due to lack of motherboard implementation.
2.64 billion transistors make up the Northern Islands Cayman core, which shares the same 256-bit bus as its predecessor the Barts core. This particular model uses the slightly cut down Cayman Pro (as opposed to the 6970's Cayman XT) with the unified shader count at 1408 vs 1536 and texture mapping units 88 down from 96.
With this in mind, we were curious to see where XFX's attempt sat in the ever increasing line-up of GPUs. XFX clocked their card slightly above the reference 800MHz core and 1250MHz memory to 830/1250. We took this further using MSI Afterburner v2.1 beta 7, pushing the voltage to 1.2v from 1.1v stock, the core clock to 950MHz, and memory to 1525MHz. Not bad!
This particular model sports a non-reference cooler with an attractive understated black enclosure with a metallic logo and stripes. Three copper heatpipes transfer excess heat from the core to the large aluminium finned heatsink. Dual fans share the load to help to dissipate this heat without making a racket, unlike single fan designs that typically run at increased speeds to keep up. Air is sucked in from within the case and exhausted through a small grille out the back of the unit. We did notice a large portion of warm air leaking from the top of the shroud, so ambient case temperature may be a concern if airflow is lacking.
Delving into the nitty gritty, our open air test bench reported a comfortable 32c at idle, and 74c under OCCTs GPU test at stock. This was matched with 45.1dB and 53.6dB on the sound level meter respectively, when utilising automatic fan control. Temperatures rose to 37c at idle, and 81c load with the aforementioned overclock, while noise remained sufficiently low with values of 45.1dB idle and 57.6dB load.
With the card revved up for testing, we threw our copy of Unigine Heaven at both stock and overclocked speed, only to come away with an impressive 12.5 per cent FPS increase in both tessellation enabled/disabled tests. Vantage took its score of P20031 further with a score increase of 9.2 per cent.
Synthetic benchmarks are nice and convenient, but there's nothing like testing on actual games. Crysis did well with an average FPS score of 48, only made sweeter by a further 13 per cent boost on our overclocked configuration. Minimum FPS went up eight per cent, and maximum FPS 13 per cent. Lost Planet experienced a milder seven per cent increase on average.
When it comes to displaying our rendered friends, we have a choice of five ports; two DVI (one single link, the other dual link), two Mini-DisplayPort v1.2, and HDMI v1.4a. Connectivity until your heart's content!
Other notable elements include a 'do not disturb' door sign (gaming: it's serious business), and a crossfire bridge as part of the bundle.
Pricewise, you can obtain the XFX xXx edition HD6950 on the streets for $355, a substantial premium over reference designs which go for as little as $283. With reference 6970 cards selling for under $400, one must decide whether a cooler and quieter overclocked 6950 is worth purchasing over shelling out for the next model up. Or, if you dare, flash the card with a 6970 BIOS and hope for the best.
Issue: 137 | June, 2012