Radeon HD 7950 review

As Nvidia continues to roll out its stack of second-generation Kepler graphics cards, we couldn't help but adjust our focus towards AMD and wonder what's going on in the red corner. To the best of our knowledge, we won't be seeing any new desktop GPU products from the firm until the latter end of the year, and in the meantime we're left with just the recently released £100/$140 effort, the rather decent Radeon HD 7790, and new editions of last year's offerings - the price/performance king being the HD 7950.

Available these days for around £230/$299, this card may not have the out-and-out performance of the top-end HD 7970 but it is very easily overclockable, with the card voltage locked to ensure that any tinkering is unlikely to have adverse effects on the card. Up against the green corner, the stock version can't quite match Nvidia's GeForce GTX 670 in performance terms, but it's priced more cheaply as a consequence and, provided you get a decent chip, overclocking should take you to a comfortable mid-point between GTX 670 and GTX 770 performance - effectively GTX 680 level then, not bad at all for the price.

But what intrigues us most about it is its 3GB of onboard GDDR5. Right now, that additional gigabyte of RAM sits there virtually unused by the vast majority of games, offering absolutely no performance advantage over the more common 2GB cards. It's mostly there in order to facilitate a 384-bit memory bus - necessary to compete with the more efficient Nvidia offerings that perform the same or better with a 256-bit interface and less RAM. But the usefulness of that additional memory could change significantly as we move into the next-gen era, with the 8GB of unified RAM present in both consoles offering an architectural advantage over the split-pool set-up seen on PC. Already we've seen hints of developers pushing the envelope - the Killzone: Shadow Fall demo from the February PlayStation 4 reveal uses 3GB RAM for graphics in its pre-production state, and when we approached developers to discuss how to future-proof your PC, all of them stressed the need to buy a graphics card which as much onboard video RAM as possible.

The Radeon HD 7950 may sit just under the top tier of current GPU performance in the £300/$400 bracket, but the non-boost version that we have here is priced accordingly, and that extra 1GB of video RAM is effectively being given away for free - as far as we're aware, it is the cheapest 3GB graphics card currently on the market today. Suddenly that year-old tech is starting to look a whole lot more interesting...

"GDDR5 memory options and AMD's choice of a 384-bit memory bus explains the 3GB configuration - an extravagance for now but potentially very useful once the next-gen consoles arrive."

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So where does the card sit in AMD's current line-up? The processor giant's most popular cards are the keenly priced Radeon HD 7850 and its more expensive HD 7870 partner, offering 16 and 20 compute units respectively. The HD 7950 is step beyond that, offering up 28 compute units plus a 384-bit memory bus, offering up a 50 per cent increase in memory bandwidth over the cheaper cards. Core frequency is 850MHz, but newer versions of the tech will auto-boost up to 925MHz provided thermal headroom is available (our card is vanilla, lacking this feature). Gigahertz Editions are also available, but we found that our vanilla HD 7950 was absolutely rock solid at 1020MHz, with RAM stable at 1370MHz (5.48GHz effective). Getting that extra performance was as simple as moving a couple of sliders within the AMD Catalyst control panel.

But at stock levels, what can you expect from a standard card? Well, we kick off our analysis with the same kind of testing criteria we used to judge performance on the considerably more expensive GTX 770. We're running the "Welcome to the Jungle" stage of Crysis 3 at high settings with very high quality textures engaged. Anti-aliasing saps performance considerably in this game - even if you're running with three Titans in SLI - so we've opted to retain our standard SMAA 2x medium preference, while v-sync is engaged in order to kill tearing. It's a tough challenge for the card - we're essentially putting it through an extremely demanding test that a GPU costing over 40 per cent more failed to comprehensively ace, and once again we're running at both 1920x1080 (1080p) and 2560x1440 resolutions. Our test set-up remains the same - we're utilising a Core i7 3770K overclocked to 4.3GHz, married up with 16GB of DDR3 RAM running at 1600MHz.

"Crysis 3 performance can leave a little to be desired in terms of frame latency and lowest frame-rates, but overall it's a good deal for the price."

Crysis 3: Radeon HD 7950 - 1080p vs. 1440p Frame-Rate Tests

Alternative comparison:

• Crysis 3: GeForce GTX 770 vs. Radeon HD 7990 vs. Radeon HD 7990 (overclocked)

Clearly, you get what you pay for. Performance is degraded compared to the GTX 770 at stock settings as you would expect, but we were surprised at just how close the HD 7950 came once our overclock was in place (there's a supplementary video that demonstrates the difference at 1440p). At the standard clock speed, we were a touch disappointed at the varying latency in frame delivery though - even at 1080p. The ride didn't feel particularly consistent and while 2560x1440 offered up considerably lower frame-rates across the board, we felt that overall performance was more level overall - a curious state of affairs.

However, factoring in the price point, plus the hitherto unknown advantages that the additional gigabyte of RAM may offer once next-gen console arrives, not to mention the rock solid overclocking potential in the card, the HD 7950 is clearly good value now. Just about the only tangible disappointment from this XFX model was that the dual-fan set-up was rather loud, even in comparison to the GTX 670 reference design's blower with its somewhat annoying whirr. However, clearly on a general level, AMD thrives on value and with the arrival of additional GTX 700 series cards for release across the summer with no direct AMD counterparts to rival them, we could well see prices on the HD 7950 fall still further.

So how does the card stack up across a range of other games versus the more expensive Nvidia offerings we've recently taken a look at? The game engine benchmark tests offered up by Metro 2033, Sleeping Dogs, Tomb Raider, BioShock Infinite, Hitman: Absolution and Metro: Last Light offer up plenty of data we can sink our teeth into. We kick off with metrics taken at 1080p with every conceivable quality setting (bar PhysX and Tomb Raider's TressFX) dialled up to the max. Additionally, in order to show some kind of context to the figures and to show the ebb and flow of performance, we've also included a video benchmark too, showing how everything plays out in real time.

Crysis 3: Radeon HD 7950 - 1080p vs. 1440p Frame-Rate Tests

"The HD 7950 lags behind the more expensive Nvidia competition on all but the most bandwidth intensive tests, but overclocking makes it very competitive."

For a card that's costs so much less compared to the opposition - even the GeForce GTX 670 - the Radeon HD 7950 hands in some fairly strong figures. Nvidia absolutely dominates in BioShock Infinite in particular, but the gap closes a touch in Tomb Raider and suddenly the HD 7950 looks much more competitive on every other benchmark we have. It's only a shame that we didn't have the GeForce GTX 660 Ti to hand to see how Nvidia's cheaper offering would have stacked up.

However, bearing in mind the much wider memory bus and the higher power requirement, it's fair to say that the HD 7950 is effectively brute-forcing its way to success here - a pattern that sees the card push to higher levels still once the 1020MHz core/1370MHz RAM overclock kicks in. Here we're seeing results that push the 7850 up to GTX 680 levels - indeed, in a couple of cases we're seeing the technology reach the giddy heights of GTX 770 performance. Chances are you'd see similar performance from the Gigahertz Editions of the HD 7950 released in recent times.

Next up, we re-ran those tests, this time upping resolution to 2560x1440, but knocking down the overall quality presets down a single notch. The idea here is to judge the card's suitability for ultra-high resolutions while at the same time accepting that ultra-quality settings at such a challenging level are only really attainable on multi-GPU set-ups. We also ran Hitman: Absolution's benchmark at both 8x MSAA and 2x MSAA to once again demonstrate just how much power is absorbed by extreme multi-sampling and that perhaps it's time to embrace more innovative anti-aliasing solutions.

As the table below demonstrates, the results speak for themselves. The yawning chasm in performance we saw between AMD and Nvidia in BioShock closes up nicely, and while Tomb Raider results aren't so strong, the Radeon HD 7950 puts in some highly creditable figures in almost all of our other remaining metrics.

"The results are pretty clear - Nvidia is more power-efficient and beats the HD 7950 in performance, despite the narrower RAM bus - but you do end up paying more for the privilege."

Radeon HD 7950 3GB: the Digital Foundry verdict

In the rush to review the latest and greatest, we often forget that vendors have plenty of existing inventory that they need to sell - last year's top-tier product becomes this year's attractive bargain buy. In the case of the Radeon HD 7950 3GB, we see prices being pressured on two fronts - this is a graphics card that is over a year old now, that has progressively lost its sheen as new Nvidia products hit the market. Worse still for AMD, in the here and now it has absolutely nothing to replace it. Seemingly the only way to keep competitive is to slash prices: the brutal reality for AMD is that the HD 7950 has lost over a third of its retail price over the last year - bad news for the company perhaps, but good news for gamers with an eye for a bargain.

While the HD 7850 and HD 7870 are generally considered the default AMD choices in terms of price vs. performance, we think that the additional power on offer here in combination with the bonus "freebie" video RAM makes it the better pick. The question of how effective the extra memory will be once next-gen consoles arrive is something of an unknown at the moment. In truth, at 1080p resolutions the vast majority of games right now run identically on both 1GB and 2GB editions of the evergreen Radeon HD 7850 - with only Skyrim's ultra settings seeing a radical shift in performance between the two cards. Certainly in the short term - where initial next-gen console titles will most likely be PC-orientated anyway - not much will change. But it may well be the case that the highest-quality texture settings will be off the table even for 2GB cards should the development focus puts consoles first.

In the meantime, the focus shifts back to Nvidia and what it has planned for the price point the HD 7950 currently occupies. On that point, we have the feeling we'll be finding out sooner rather than later.