Testing AMD’s Radeon HD6870, HD6850, and Nvidia’s GTX 460 review

Posted by Jon Peddie on October 29th 2010 | Discuss
Categories: Hardware Review
Tags: gpu nvidia amd ati radeon gpgpu pmark graphicscard ghtx

Performance segment AIBS

Figure 1: Three AIBs: AMD Radeon HD6870, HD6850, and Nvidia GTX 460

It’s times like these, and last week, when AMD and Nvidia roll out their latest offerings where we get to see what they’re made of and how well they do in games and compared to each other. In the last issue we checked out the mainstream offerings of the leading AIB suppliers¹ and this week we’re putting the Performance segment units, AMD’s new Radeon HD6870, and HD6850 AIBs up against Nvidia’s new GTX 460 AIB.

We ran all the tests on an Intel Core i7 x980 3.33 GHz, machine with 3 GB RAM, running Windows 7 - 64bit. The configuration of the AIBs are:

Table 1: AIBs tested.
	HD 6870	HD 6850	GTX 460 (EVGA)
Core Clock	900 MHz	775 MHz	850 MHz
Memory Clock	1 GHz	1 GHz	1 GHz
Memory	1024 MB	1024 MB	1024 MB
Driver	10.1	10.1	260.89
Power	151	127	160
Processors	1120	960	336
Transistors	1.7 B	1.7 B	1.95 B
Price $	$239	$179	$220

AMD. The AMD Radeon HD 6800 series AIBs are built using a new GPU code-named Barts. It's a modified version of the Cypress GPU featured in the Radeon HD 5850 and 5870 graphics AIBs. The Barts is slightly smaller in processors and doe size than the Cypress but still delivers excellent performance. Be sure to check out Jon’s overview of the Barts GPUs and its architecture for a look at what's happening under the hood.

Nvidia. The Nvidia GTX460 is the latest member of the growing Fermi GPU family, and is targeted at the same part of the Performance segment as AMD’s new Barts parts. The GX460 is a derivative part that has a lot of headroom in it which has allowed Nvidia’s partners to come out with special, and more expensive, over-clocked versions.

First impressions

We ran four benchmarks on three AIBs: Unigine Heaven, Metro 2033, Stalker COP, and Lost Planet. We ran the tests at 1680x1050 4x AA, 1920x1200 4x AA, and 2560x1600 4x AA, which gave us twelve test points for three AIBs for a total data set of 36 points.

We then take an average of each resolution series for each AIB, and then the average of the three to arrive at “the performance” value for the AIBs. We then use that performance value in our performance per dollar calculation and in our Pmark calculation.

The rationalization is no one is going to buy an AIB to just play one game, and so average performance across several games and at various resolutions is more useful to the buyer. However, the raw data as mentioned is also provided so the AIB supplier can find the data point they need to beat their chests about.

Pmark and Performance per dollar

There are two variables in arriving at these scores – the softness of the AIB’s price (from the time we started this piece till it was finished we saw prices drop by $10 to $25 as the suppliers tried to jockey for best position.

The other variable is over clocking. We did use an AIB that was sent to us set up in an over-clocked mode. Over-clocking is a waste of time discussion, and in our opinion BS. If you can turn up the clock on an AIB and it works, and it delivers better performance, so what? That sounds like more value for money to us, not cheating. As long as the AIB supplier guarantees the AIB to run at that clock what’s the issue?

Pmark is calculated as:

Pmark

The PMark

Where:

Performance is Total Score
Price is expressed in US dollars
Power is expressed in watts of the AIB

Table 2: Tested AIB’s Performance
	HD 6870	HD 6850	GTX 460 (EVGA)
Pmark	0.081	0.116	0.100
Perf/Watt	0.19	0.21	0.22
Performance/Dollar	0.12	0.15	0.16
Average Performance	29.2	26.4	35.2

What do we think?

It comes down to how the end user will make a decision. If it’s all about performance and $40 or 23% isn’t criti- cal to the budget then the over-clocked Nvidia GTX 460 is the best choice. If the user wants an economical yet plenty powerful AIB then the AMD Radeon HD6850 is the best choice based on the above test results.

Other factors. The AMD AIBs can drive more displays simultaneously. Consider Table 2.

If you want to drive a lot of dis- plays AMD is the hands down winner. Both AMD and Nvidia are limited by PLLs and can only afford to drive two or three outputs between the DVI and HDMI, but DisplayPort runs indepen- dently of that and so can output simul- taneously, making the HD68x0 capable of driving four displays at once either as a single large surface or as extended desktop

GPU-compute. All the AIBs are ca- pable of GPU-compute. Nvidia holds a lead in that area with support for CUDA and OpenCL (and others), whereas AMD only supports OpenCL. For the average consumer it’s a don’t care as all the consumer video applica- tions now support both OpenCL and CUDA, and soon all the photo editing programs will too.

These are damn fine AIBs, lots of value and features for the money, and you could almost play spin the bottle in the selection and would you wouldn’t go wrong.

Figure 2: Pmark for AMD HD6870, HD6850, and Nvidia GTX460