Gigabyte HD7970 OC Review Page: 1

Gigabyte HD7970 OC Review


The last generation of Radeon graphics cards was most definitely a hot noisy bunch. One of the biggest changes with the Tahiti GPUs has been how relatively cool and quiet the HD7970s have been. However, being cool and quiet in reference terms is one thing, but we all know that even the best reference coolers can be bettered with something a bit more robust in the heatsink department.

The other big quality that the HD7970 has is overclocking. Even basic cards can be pushed into 1200MHz and beyond. They overclock as easily as almost anything we've come across so it's no great surprise that we're getting some cards coming out from the manufacturers with decent overclocks 'out of the box'

First up in the big overclock/third-party-cooler line is Gigabyte with the HD7970 OC, replete with their Windforce cooler we last saw on a GTX560Ti 448.

Technical Specifications

The big number you can't help but swoon at is the 1000MHz default clock speed. If you're one of those people who don't like overclocking your £500 purchase then this will obviously be something that should push the Gigabyte high up your list.

ChipsetRadeon HD 7970
Digital max resolution2560 x 1600
Analog max resolution2048 x 1536
Process Technology28 nm
Core Clock1000 MHz
Memory Clock5500 MHz
Memory Size3072 MB
Memory Bus384 bit
Card BusPCI-E 2.1
Memory TypeGDDR5
DVI-I x 1
Mini DisplayPort x 2
Card sizeH=38 mm, L=285 mm, W=126 mm
Power requirement550 W

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Gigabyte HD7970 OC Review

Up Close

The packaging is often only worth a cursory mention unless it's particularly stunning or terrible. The Gigabyte is worth a shout because it's so nice to see something different in the artwork. The combination of neon, almost Tron-esque, and some very clean design choices really brings us something that feels modern, rather than the 80s stuff we're used to.

Gigabyte HD7970 OC Review     Gigabyte HD7970 OC Review  

Not only is the Gigabyte HD7970 OC a triple-fan cooler but we also have the classic Gigabyte standby of a blue PCB. These are definitely an acquired taste, especially when you nearly always are only looking at the back of the card due to the horizontal mounting we're all use to.

Gigabyte HD7970 OC Review     Gigabyte HD7970 OC Review  

Speaking of the cooler, it's a stunner. Heat-pipes and insane fin density should ensure that the card remains frosty at all times.

Gigabyte HD7970 OC Review     Gigabyte HD7970 OC Review  

Despite the factory overclock and increased amount of fans the Gigabyte still only needs an 8pin and 6pin PCIe power input. Round the business end we have the now standard arrangement of a single DVI and HDMI, as well as two mini-DisplayPorts.

Gigabyte HD7970 OC Review     Gigabyte HD7970 OC Review

Gigabyte HD7970 OC Review Page: 3

Gigabyte HD7970 OC Review

Test Setup

Gigabyte HD7970 OC Windforce Edition
Catalyst HD7970 Drivers 11.12
Intel Core i7-3960X @ 4.6GHz
ASUS Rampage IV Extreme
2x Corsair AX1200W
Corsair GTX8
Corsair H100
Noctua NF-F12 Fans
Windows 7 Ultimate x64


Despite coming from the factory at 1000MHz you know we wouldn't just leave it at that. Some gentle tweaking later and the Gigabyte is rock-solid stable at a stunning 1300MHz. Hopefully the results will bear out our monster overclock.

Gigabyte HD7970 OC Review Overclock


Let's get one thing straight, this is whisper quiet. It's no louder than the Noctua's on our H100. It's not only about noise though, look at those temperatures. The coolest HD7970 by about 10°C!!

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Gigabyte HD7970 OC Review

3D Mark 11

With the fastest stock speed of an of the 7970s we've tested, and the highest overclock, it's not a surprise to see the Gigabyte leap to the top of our 3D Mark 11 charts. Cracking 10000 P score with a single GPU is stunning.


3D Mark Vantage

Surprisingly the Vantage P score doesn't replicate the results we saw from 11, with neither the stock nor overclocked results matching up to the VTX and PCS respectively.

With the test set to the Extreme preset the clockspeed shines through and takes the Gigabyte to the top of the pile.

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Gigabyte HD7970 OC Review


First up the blocks is Alien vs Predator. Always a gorgeous looking thing despite its age, and the Gigabyte handles it with aplomb, just edging the HD7970 chart.


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Gigabyte HD7970 OC Review

Batman Arkham City

As you can see from our graph Arkham City isn't the most reliable test around in terms of giving consistent results. Not only is the Gigabyte slower than its lower-clocked contemporaries, but the overclock is slower than the stock. Holy curious results.


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Gigabyte HD7970 OC Review

Battlefield 3

We know one member of our forums who will be pleased to see the Battlefield 3 graph. With the overclock comes a nicely linear improvement in performance, although the Gigabyte doesn't quite reach the heights of the PCS overclocked HD7970, or even the HIS HD7950, at stock it's capable of giving a very playable experience such is the big factory overclock.


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Gigabyte HD7970 OC Review

Dirt 3

Whilst we await the curiosity of Showdown and the more rally-focused Dirt 4, the hooniganism of Dirt 3 shall have to suffice. Strange things seem to be happening again with the Gigabyte seemingly unable to make the most of the GPU speed to outperform either the VTX3D stock result, or the PCS overclock.


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Gigabyte HD7970 OC Review

Far Cry 2

A different game but the results are the same. Sure it's only a frame here and there, but it's consistently a frame or two behind the zenith we've seen from other cards.


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Gigabyte HD7970 OC Review

Mafia 2

Despite using an identical test rig in all of our tests, and the same Catalyst drivers, the Gigabyte OC still isn't quite keeping up.


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Gigabyte HD7970 OC Review

Metro 2033

Finally we're getting a bit of a performance boost from the factory overclock of the Gigabyte with a very respectable 52 FPS. The overclock doesn't help us much, but we know how finicky Metro 2033 can be.


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Gigabyte HD7970 OC Review

Resident Evil 5 DirectX 9

Even the ultra-consistent Resident Evil 5 isn't capable of making the most of the Gigabyte. Or shall we say the Gigabyte isn't making the most of the excellent Capcom game.


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Gigabyte HD7970 OC Review

Resident Evil 5 DirectX 10

At least it's consistent. In DirectX 10 we see very similar results as we had from the DirectX 9 test. Still nowhere near the other HD7970s we've tested.

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Gigabyte HD7970 OC Review

Unigine 0xAA

Now we're back in the world of the synthetic benchmark the Gigabyte once again shows its colours and flies to the top of the graph.


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Gigabyte HD7970 OC Review

Unigine 8xAA

Pushing the HD7970 to the limits with the addition of 8xMSAA and the Gigabyte HD7970 OC keeps on kicking, with a healthy 2-3FPS over the other models we've tested.


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Gigabyte HD7970 OC Review

The Witcher 2

As we finish up with a game, we return to the Gigabyte underperforming. Hmmm.


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Gigabyte HD7970 OC Review


If the Gigabyte HD7970 OC can be likened to a Batman character, it's obviously Harvey Dent. It's most definitely a two faced card, but with an ace up its sleeve.

Let's start with the good. It's always nice to start with the positives.

The HD7970 is a monster performer, of that there is no doubt. It's the current performance king and if you're after the biggest benchmark results then it's the only choice. Benchmarks is exactly where the Gigabyte OC shines. In 3D Mark 11 it gave the best single-GPU scores we've seen by quite a distance thanks to a combination of the 1000MHz 'stock' clock speed and that brilliant cooler which allowed us to push it to a mighty 1300MHz. Even in 3D Mark Vantage we saw some phenomenal X marks, although the P-Score wasn't quite up there with the best we've seen. Of course Unigine Heaven is about as stern a test as you're likely to see that isn't a game, and once again the extra burst of performance the Gigabyte HD7970 OC has allows it to rise to the top.

Gaming results were much less impressive. Don't be in any doubt that you'll get a whopping amount of performance out of the card and you wont at all be disappointed. But we're in very elite company here and at this high-end level those fine margins can make the difference. The Gigabyte was consistently slower in average frame-rate at stock than our reference VTX3D HD7970 despite having a 50MHz improvement in clock speed. The highest overclock we've yet obtained managed to get closer to than we saw at stock, yet still the results didn't fully bear out the amount of performance we theoretically had. It might only be three or four frames per second on average, but the fact it had consistently lower performance in gaming is a bit of a worry for those seeking ultimate power.

The absolute star of the show is the Windforce cooler. We cannot emphasise enough how quiet it is. Even when it had been running, overclocked, the extremely demanding Unigine Heaven benchmark for over an hour it was still as quiet and refined as the Noctua fans that help keep the CPU cool. It wasn't a case of everything being sacrificed on the altar of silence either, as the Windforce cooler dropped the HD7970 a whopping 10°C when compared to the reference cooler. It's stunning. Amazing.

So all in all it's a little bit of a mixed bag in that you're sacrificing a little gaming performance for the benefits of silence and coolness, along with high overclocks and big benchmark scores. Deciding what award to give it is tricky. Sure the cooler is stunning, and the synthetic benchmarks are amazing, as is the overclock. But we've seen higher gaming performance from reference cards at lower clocks, which makes you wonder what the extra MHz is doing. However we'll edge down just on to a Gold because of the magnificence of that cooler and the closeness of the performance. If another card marries the brute performance with a similarly great cooler it would leave the Gigabyte as more of a Silver, but for now it's good enough for Gold.


Thanks to Gigabyte for supplying the HD7970 OC for review. Discuss in our forums.