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Today's graphics cards: the value angle


How much GPU does your dollar get you?
— 7:26 PM on May 7, 2008

The last time we attempted to quantify the value propositions of a large cross-section of competing products, we concentrated on microprocessors. Ever since then, we've wanted to explore the same concept with graphics cards. Thanks to our latest round of graphics card reviews, which culminated with the massive GeForce 9 series multi-GPU extravaganza last month, we've ended up with enough benchmark data to paint a fairly complete picture of today's mid- to high-end GPU market.

Armed with this information, we've taken another crack at quantifying value, this time by looking at what sort of GPU power you get for your dollar. The results are interesting, if nothing else. Read on to see what we found.

Quantifying GPU value
This is an iffy exercise, this attempt to quantify a value proposition that often involves considerations one can't easily boil down to numbers. We have no illusions that this little thought experiment will yield the only or best information you need in order to decide which graphics card to buy. Our graphics card reviews include a mix of subjective impressions and objective test data, and they're probably your best starting point in these matters.

Heck, even if you want to go purely for a "raw value" approach, you may be better served by looking at one of our recent reviews, like the aforementioned GeForce 9 multi-GPU extravaganza. You could conceivably just hunt for the cheapest card that achieves playable frame rates at (or near) your monitor's native resolution and call it a day. There's nothing inherently wrong with that, and it's certainly a very value-oriented approach. But it won't get you anything much in the way of future-proofing, and it won't tell you how much graphics processing capability you're getting for your money.

For this article, we wanted to focus more closely on the question of GPU power per dollar. To make that work, we've relied on test data from (as much as possible) clearly GPU-limited scenarios—performance results obtained at very high resolutions (most often 2560 x 1600) with some level of antialiasing and anisotropic filtering enabled. That way, we can highlight questions of performance scaling. We can see how the cut-down shader power and memory capacities of the less expensive cards impact performance and observe how much multi-GPU solutions can distance themselves from their single-GPU brethren.

Obviously, concentrating on GPU-limited scenarios like these sidesteps the question of "playable frame rates" in today's games, as we've noted. Vast differences in GPU power may not be readily apparent at 1680x1050 in currently popular titles, but they may become very important in the future as game developers ratchet up the shader effects and scene complexity, packing more richness into each pixel. Our hope is that we can help you make a more informed evaluation of the value proposition, one that considers how your video card might serve you over its entire lifespan.

Our test subjects
Anyway, let's have a look at our subjects. We've included results for 20 GPU configurations in total, nine of which are single cards...

Single card GPUs Price
Radeon HD 3850 1 $154.99
GeForce 9600 GT 1 $159.99
Radeon HD 3870 1 $164.99
GeForce 8800 GT 1 $189.99
GeForce 8800 GTS 512 1 $254.99
GeForce 9800 GTX 1 $309.99
Radeon HD 3870 X2 2 $389.99
GeForce 8800 Ultra 1 $519.99
GeForce 9800 GX2 2 $549.99

...and 11 are multi-card setups:

Multi-card setup GPUs Price
Radeon HD 3850 CrossFire 2 $309.98
GeForce 9600 GT SLI 2 $319.98
Radeon HD 3870 CrossFire 2 $329.98
GeForce 8800 GT SLI 2 $379.98
Radeon HD 3870 X2 + 3870 3 $554.98
GeForce 9800 GTX SLI 2 $619.98
Radeon HD 3870 X2 CrossFire 4 $779.98
GeForce 9800 GTX SLI 3 $929.97
GeForce 8800 Ultra SLI 2 $1,039.98
GeForce 9800 GX2 SLI 4 $1,099.98
GeForce 8800 Ultra SLI 3 $1,559.97

You might wonder where we sourced the prices listed above. In our CPU value article last year, we simply took bulk prices directly from AMD's and Intel's respective websites. Real-world CPU prices fluctuate and don't necessarily reflect bulk pricing, but the two are often pretty close, and bulk prices have the benefit of coming from "official" sources.

Graphics card pricing is a very different matter. AMD's and Nvidia's official launch prices for new GPUs are only loose guidelines, and they often cover a range of possible prices—for instance, "$199-249" for the GeForce 8800 GT. Cards usually drift from their launch prices ranges after a while, too, so we were left with no option but to nab prices from online retailers. In the end, we relied on a mix of prices from Newegg and our price search engine. Overall, we believe the figures we picked should do a good job of representing typical real-world pricing.

We ran into a little snag while collecting prices for the Radeon HD 3850 and GeForce 9600 GT, however, since the models we tested are both significantly marked-up "overclocked in the box" models. To avoid skewing our data too much, we looked for cheaper cards with similar clock speeds. We selected a GeForce 9600 GT with 700MHz core and 950MHz memory speeds to be our price reference for the 700MHz/1000MHz card we tested, and we picked a 720MHz/910MHz Radeon HD 3850 to do the same for our 725MHz/900MHz test model. Those slight clock speed differences shouldn't impact performance too substantially, and the lower prices are better indicators of what you can expect to pay for a Radeon HD 3850 or GeForce 9600 GT these days.

Presenting the data
We have our reasoning, our performance results, and our prices. Here's how we sliced and diced the data to give us some insight.

We carried over two tools from our CPU value comparo. One is the simple "performance per dollar" chart, which, in this case, ranks cards based on how many frames per second $10 will buy. The exact formula is: ((frames/second)/price))*10. We relied on our good friend Alexander Hamilton rather than his buddy George Washington for this task, because ranking cards based on FPS per dollar yields hard-to-read numbers with too many leading zeros.

Ranking performance per dollar doesn't give us the whole picture, though—far from it. As you'll see in the next few pages, the one card that ranks highest in performance-per-dollar charts is usually the cheapest (and thus the slowest), and it's often followed by slightly slower but equally expensive competitors. To get a look at which cards lie in the proverbial "sweet spot" of price and performance, we used scatter plots like this one:

These scatter plots may look a little intimidating, but they're really quite simple. The best possible offering would be in the top left corner, offering the highest frame rate for $0, while the worst possible one would be at the bottom right, yielding 0 FPS for the most money. We obviously never get such extreme cases, but the best offerings still typically lie closer to the top left corner of the plot. In the example above, the GeForce 9600 GT looks to be a better deal than either the Radeon HD 3870 or the Radeon HD 3850. The GeForce 9600 GT SLI config puts in a very good showing, as well. Conversely, the GeForce 9800 GTX three-way SLI setup is a poor value.

Now that that's (hopefully) clear, let's move on to the benchmarks.