Radeon HD 7970 vs GTX 770 graphics card comparison review

AMD Radeon HD 7970 and nVidia GTX 770

The AMD Radeon HD 7970 and nVidia GTX 770 may seem like evenly matched graphics cards in terms of price, but these products differ more than you would think. We'll take an in-depth look at their specifications, and try and explain which of the two offers the best technology, and whether this translates into the best performance and value for money. Read on for our lowdown on these two titans of the mid-range graphics market. (See also: nVidia GTX 760 v Radeon HD 7950 GPU comparison: which is the best mid-range graphics card? and AMD Radeon R9 280X vs nVidia GeForce GTX 770 comparison review.)

AMD Radeon HD 7970 vs nVidia GTX 770: Out with VLIW and In with GCN

The 7970 and 7950 series marked a very significant turning point for AMD in its fight to remould the gaming landscape. Initially, nVidia and AMD were offering GPUs with very different world-views. The 'scalar' architecture of nVidia aimed for great versatility, and could think very quickly on the fly. This was in direct contrast to AMD's 'vector' VLIW (Very Long Instruction Word) technology, which was brilliant at bulldozing 3D graphics, but which would quickly get confused when faced with more general tasks. As the PC market moved closer towards applications like Compute, the lack of versatility of VLIW looked like being a problem.

So with the 7970 (the Tahiti XT), the first in its Southern Islands range, AMD introduced a brand new type of architecture - GCN or Graphics Core Next - which falls more into line with nVidia's scalar approach. The potential of GCN is undoubted, with a 7.5x upgrade on computer performance promised, for instance. For the typical user, though, it's still likely to be the gaming capabilties that will define whether this is a hit or a miss.  

The GCN-esque approach, of course, is pretty old-hat in the case of the GTX 770, and nVidia has been pushing a similar concept for many years now. In many respects, though, the GTX 770 seems a bit of a throwback. It's built around the GK104 (Kepler), one of nVidia's most tried and trusted chips, and the GK104 has made an appearance in a range of differing nVidia products, from the now ageing GTX 660 and 680, to the newer GTX 750 and 760. Indeed, while the GTX 770 is the newer GPU (having been released in mid-2013 rather than the early 2012 of the 7970 Tahiti XT), it frequently gives the impression of being less sophisticated and worldly.

AMD Radeon HD 7970 and nVidia GTX 770Both the GTX 770 and Radeon 7970 are created using the 0.28nm manufacturing process, but the AMD packs in the greater number of transistors - 4.31 billion rather than the 3.5 billion of the GTX 770. There's also the question of memory. The GTX 770 was initially launched as a 2GB version, although an additional 4GB incarnation has since been unleashed. The 7970's default version, though, is already armed with a healthy 3GB, while a 6GB version has also been available on occasions - although no such card is around now.

It's not always helpful to compare differing technologies, but the 7970 fares well on specifications generally. The 7970 sees that Tahiti chip working at a high level, and all 32 of the CUs (computing units) are turned on. That allows it to achieve a full 2048 stream processors, and 128 texture units and 32 raster operations. This places it very much on a par with the  Radeon R9 280X, a considerably newer (late 2013) product that is built around the same Tahiti chip. The GTX 770 is similarly at the top of its tree, using the full eight SMXes (Streaming Multiprocessors) offered within the GK104 chip, and also touting the same 128 texture units and 32 raster operations of the 7970. The GTX 770 does fall a little on streaming processors, and its complement of 1536 sees a 25% reduction on the 7970's figure. See also: GTX 760 vs GTX 770 GPU comparison review: Which GK104 Kepler graphics card is best?

AMD Radeon HD 7970 and nVidia GTX 770: higher-end for higher-compute?

Modern graphics cards are muddying the waters between gaming machines and those used for higher-end more-serious work. Should your needs fall into the latter category, you may be interested in the Compute capabilities of these two GPUs. Well, in all honesty, neither is going to double up as a high-end Quadro/Tesla-replacement. For that you need to be looking to the GTX Titan or the Radeon R9 280X.

However, there is a difference between the 7970 and the 770. Strangely, given the 770's latent power, it's not terribly good at handling the FP64 (64bit double-precision) calculations important in many of the highest-end applications. Its performance here falls to a mere 24th of the FP32 showing. With its newer framework, the Radeon HD 7970 fares far better here, seeing it achieve a quarter of its FP32 performance when working with FP64 calculations - that's a relatively modest decline.

Indeed, the 7970 isn't far behind the brand new R9 280X, showing that AMD's change to GCN was a very wise move. Later nVidia GPUs have fixed this somewhat, but the GTX 770 is very much behind the times. That's unlikely to be a problem for most gamers, but the 770 is definitely a more narrow-minded and less versatile product. (See also: Group test: what's the best budget graphics card?)

AMD Radeon HD 7970 and nVidia GTX 770: core clock speeds

Not that the GTX 770 is behind its rival in every area. Indeed, that compact size and lower transistor count means that the 770 can be safely driven at higher clock speeds. Even at its relatively modest factory settings, it achieves core speeds of 1046MHz, with a Boost clock capable of driving it at up to 1085MHz. Hunt around for a top commercially overclocked board using the GTX 770, and you can find several great examples that push the core clock right up to 1,202MHz. This is a very marked difference to the 7970, which hits a default speed of just 925MHz. There's no Boost, so that leaves its top speed trailing some 160MHz behind the 770's. You can buy overclocked versions that get it up to the 1GHz mark, but this is still over 200MHz down on the very best GTX 770s.

Both the 770 and the 7970 share the same number of texture units (128), so texture fill rates effectively come down to the clock speeds. Unsurprisingly, then, the 770 scores a notable victory here, achieving rates of 138.9GT/sec rather than the 7970's 70.4GT/sec. The very fastest GTX 770 boards have fill rates close to 154GT/sec. It's of course possible to buy a 1GHz version of the 7970, and get its own figure up to 128GT/sec, but that remains a very pale imitation of the best 770s. The 7970's lack of a Boost is a real problem for it, and it consigns it to a desultory performance here. (See all budget graphics card reviews.)

AMD Radeon HD 7970 and nVidia GTX 770: memory clock speeds

AMD Radeon HD 7970 and nVidia GTX 770Initially, the memory clock speeds would appear to write a similar story. Again it's that less complex interior that allows the 770 to operate at much higher rates. Even at factory settings, its memory clock of 1.75GHz meshes with the quadrupling capabilities of the memory to produce a stunning effective clock rate of 7GHz. This really is pushing existing memory to the brink of what it can do, and the 7GHz figure is a remarkable benchmark. The 7970 falls some way short, its 1.375GHz clock producing an effective rate of 5.5GHz. We should point out that this isn't atrocious. Even the R9 280X only reaches 6GHz in its default incarnation, as do a variety of other cards, including the GTX 760. Nonetheless, the 770 appears superior here.

There is something of a twist, though. That's because the 7970 keeps an alluring trick up its sleeve in the shape of its vastly superior 384bit memory interface. That's considerably wider than the GTX 770's 256bit version, and means that the 7970 makes light work of the 770's clock rate advantage. Bandwidth calculations show that the 7970's memory subsystem works better overall, returning a stunning rate of 264GB/sec, comfortably superior to the GTX 770's figure of 224GB/sec. It's worth noting that the R9 280X (similarly kitted out with a 384bit interface) achieves greater results still, turning out a barnstorming 288.4GB/sec. However, when it comes to comparisons between the GTX 770 and 7970, the latter reiterates that sizeable advantage it appeared to wield on raw specifications alone.

AMD Radeon HD 7970 and nVidia GTX 770: is 2GB sufficient?

The GTX 770 comes with both 2GB and 4GB versions, even if the latter will set you back an extra £40 to £50. The 7970, though, comes with 3GB as default. Does the extra 1GB of the 7970 make it the best deal, or are you better off with the 4GB 770? The answer will really depend on your aspirations for the card.

For standard single-screen gameplay, on existing titles, there's rarely more than a frame or two in it, even if you're comparing 2GB to 4GB. However, as games get more complex, and there are more textures to juggle, an extra gigabyte or two will start to make a difference. Dual-screen setups, where the resolution goes beyond 2560x1440/1600, will benefit from more than 3GB/4GB, particularly if you're intending to make use of the card for a few years yet.

If the 770 is intended to be a longer-term card that should remain highly playable for two years or more, 4GB is probably the safer bet - an extra 20% on the price will, ultimately, make little difference. For standard single-screen gaming, though, a 2GB version will suffice.

AMD Radeon HD 7970 and nVidia GTX 770: power and gaming for the big screen

Both GPUs offer the same number of Raster Operations - 32. Both are capable of very smooth three-display gaming, although only the GTX 770 also benefits from PhysX support. In all honesty, this feature remains something of a gimmick, and we have yet to see games programmers mine it for its full potential. Nonetheless, it is one small feather in the cap for the GTX 770.

The GTX 770 is also a victor in terms of power output, albeit by a relatively small amount - the nVidia's TDP of 230 watts is 20 watts down on the 7970's figure of 250. In testing, the difference was a little smaller than this, but certainly it went into the double figures. Happily, both GPUs are fairly discreet, with very little to pick between them in terms of noise levels. The GTX 770 was marginally quieter in testing, but not by more than a decibel. See Group test: what's the best graphics card?

AMD Radeon HD 7970 and nVidia GTX 770: benchmark tests

The proof is in the pudding, as they say, and so the success of graphics cards is measured by how they fare in real-world games. We've pitted the Radeon 7970 and GTX 770 against one another at default settings, and over four different titles and three resolutions. So that you've got a card to compare them to, we've also included details of a GTX 760 (at round about £200).

Crysis 3

  Crysis 3 Crysis 3 Crysis 3
  1,680x1,050 1,900x1,200 2,560x1,600
GTX 770 54.8 45.1 28.4
Rad 7970 40.1 32.6 18.9
       
GTX 760 42.9 33.8 18.7

The 770 starts with a commanding victory at the lowest resolution of 1680x1,050, scooping up an assured 13.7fps lead over the 7970. The lead only slightly dwindles (to 9.5fps) at the highest resolution, even as it actually rises significantly in percentage terms. The 760 is marginally faster than the 7970 at the lower resolutions, although the 7970 does overhaul it (albeit by just 0.2fps) at 2,560x1,600.

Bioshock Infinite Rage

  Bioshock
Infinite Rage
Bioshock
Infinite Rage
Bioshock
Infinite Rage
  1,600x900 1,900x1,200 2,560x1,600
GTX 770 99.6 76.4 44.0
Rad 7970 83.4 66.6 34.5
       
GTX 760 78.9 59.9 34.7

You can book this in as another cruise for the 770, and its close-to three-figure frame rate at 1,600x900 lays down a standard the 7970 can only aspire to, falling behind by 16.2fps. It looks a little better at 2,560x1,600, although even here the lead remains 9.5fps. The 760 is a solid distance behind the 7970 at the two lower resolutions, although it just edges 0.2fps ahead at 2,560x1,600.

Battlefield 3

  Battlefield 3 Battlefield 3 Battlefield 3
  1,600x900 1,920x1,080 2,560x1,600
GTX 770 101.0 80.6 39.7
Rad 7970 84.9 65.7 33.2
       
GTX 760 85.3 66.6 33.8

The 770 pours it on here, building a confident 16.1fps lead over the helpless 7970. The figures look more respectable at 2,560x1,600, that lead having dribbled away to 6.5fps. Nonetheless, this is more about the demanding detail levels we've bolted on rather than anything to with a resurgence. The 760 is marginally ahead of the 7970 in two of the three resolutions, but the lead remains a very minor one.

Assassin's Creed 3

  Assassin's
Creed 3
Assassin's
Creed 3
Assassin's
Creed 3
  1,600x900 1,920x1,080 2,560x1,600
GTX 770 83.2 69.1 46.8
Rad 7970 68.1 55.2 37.9
       
GTX 760 66.8 54.0 37.7

The 770 finishes with another accomplished 15.1fps lead, and it retains a healthy 8.9fps advantage even at the highest resolution. Once again the 7970 and 760 are close, although the 7970 retains a lead the whole way through - as much as 1.3fps ahead at the lowest resolution.

AMD Radeon HD 7970 and nVidia GTX 770: verdict

The 7970 is starting to slip from the market, so this might be causing the price to go a little higher than it should. Hunt around, and you should be able to buy a 3GB 7970 for around £250-£260 - particularly from Ebay. In all honesty, while the 7970 fares better on Compute applications, this is unlikely to be of any real relevance to gamers hankering after either of these products. And for raw gaming, the 770 is very much superior, often notching up double-figure leads. Given the 770's greater availability, and its performance gap, we'd certainly recommend the 770 over the 7970. We'd be needing to get a price of around £200 on the 7970 before we considered it better value.

Unless you have a need to go up to larger memory capacities, we'd recommend the 2GB 770, just on value alone. However, dual- or triple-screen setups would benefit from 4GB. As would those who'll be wanting the card to remain fresh through 2016 and into 2017. For most of us, though, the 2GB GTX 770 is simply a strong unsubtle graphics cruncher that should keep us stoked in relative frame-rate luxury for the next two years or so.

GTX 770 cards available

£252 - MSI GTX 770 Twin Frozr - 2GB, Core Clock 1,098MHz (1,150MHz Boost), Memory Clock DDR Effective 7GHz, 2yr Warranty
£270 - Asus GeForce GTX 770 DirectCU OC - 2GB, Core Clock 1,058MHz (1,110MHz Boost), Memory Clock DDR Effective 7GHz, 3yr Warranty
£276 - Gigabyte GeForce GTX 770 WindForce 3x OC - 2GB, Core Clock 1,137MHz (1,189MHz Boost), Memory Clock DDR Effective 7GHz, 3yr Warranty
£300 - KFA2 GeForce GTX 770 LTD OC - 2GB, Core Clock 1,150MHz (1,202MHz Boost), Memory Clock DDR Effective 7GHz, 2yr Warranty
£320 - Gainward GeForce GTX 770 Phantom - 4GB, Core Clock 1,046MHz (1,085MHz Boost), Memory Clock DDR Effective 7GHz, 2yr Warranty
£330 - Inno3D GeForce GTX 770 iChill Herculez 4096MB - 4GB, Core Clock 1,150MHz (1,196MHz Boost), Memory Clock DDR Effective 7.2GHz, 3yr Warranty
£360 - EVGA GeForce GTX 770 Classified ACX 4096MB - 4GB, Core Clock 1,150MHz (1,202MHz Boost), Memory Clock DDR Effective 7GHz, 3yr Warranty

When it comes to value, the 2GB cards are the ones to seek out. The Gigabyte and KFA2 tout some superb figures, particularly when it comes to the Boost clock speed. But you don't need to wring out every last ounce of pace, at the expense of price. The MSI is superb value for money, with a strong 1,150MHz Boost clock - you'll notice very little difference between this and the KFA2. If you're buying a GTX 770 for the longer term, though, you'll probably find it best to spend the money on double the RAM. The Inno3D is a great choice here, with an appetising £330 price tag, and a 1,196MHz Boost clock. You're unlikely to find the EVGA to be worth the extra £30, ravishing though it may be.

Radeon HD 7970 cards available

£260 - HIS HD 7970 IceQ X2 - 3GB, Core Clock 925MHz (No Boost), Memory Clock DDR Effective 5.5GHz, 2yr Warranty
£315 - Gigabyte 7970 - 3GB, Core Clock 1GHz (No Boost), Memory Clock DDR Effective 5.5GHz, 3yr Warranty
£340 - Sapphire Radeon HD 7970 Vapor-X - 3GB, Core Clock 941MHz (No Boost), Memory Clock DDR Effective 6,008MHz, 2yr Warranty

With the likes of the R9 280X coming along, the 7970s are starting to slip off the market. That's pushed the prices up, and in all honesty, you shouldn't be wanting to pay more than the £260 price for one of these - indeed, we'd recommend keeping an eye on Ebay to see if you can snap up one for considerably less than this. The HIS remains the best of the widely-available 7970s. Its specs are nothing to write home about, but it's not worth paying an extra £55 or more in order to get a 1GHz clock. See all PC Components and Upgrades reviews.

nVidia GeForce GTX 770: Specs

  • nVidia GeForce GTX 770
  • 2GB GDDR5
  • 1006MHz core clock (1058MHz Boost)
  • 1.75GHz memory clock (7010MHz DDR effective)
  • 400MHz RAMDAC
  • 256-bit memory interface
  • 1536 stream processors
  • 128 texture units
  • 32 ROP units
  • PCI Express interface
  • DirectX 11
  • 2x DVI, 1x HDMI
  • 1x DisplayPort
  • 1x 6-pin, 1x 8-pin PSU connector needed
  • 3-year warranty
  • nVidia GeForce GTX 770
  • 2GB GDDR5
  • 1006MHz core clock (1058MHz Boost)
  • 1.75GHz memory clock (7010MHz DDR effective)
  • 400MHz RAMDAC
  • 256-bit memory interface
  • 1536 stream processors
  • 128 texture units
  • 32 ROP units
  • PCI Express interface
  • DirectX 11
  • 2x DVI, 1x HDMI
  • 1x DisplayPort
  • 1x 6-pin, 1x 8-pin PSU connector needed
  • 3-year warranty

OUR VERDICT

Unless you have a need to go up to larger memory capacities, we'd recommend the 2GB 770, just on value alone. However, dual- or triple-screen setups would benefit from 4GB. As would those who'll be wanting the card to remain fresh through 2016 and into 2017. For most of us, though, the 2GB GTX 770 is simply a strong unsubtle graphics cruncher that should keep us stoked in relative frame-rate luxury for the next two years or so.