AMD Radeon HD 7770 1GB vs. nVidia GeForce GTX 650 Ti 1GB

The best card under $160.9, but it still underpowered

Wild bunch: 15 – 20 per cent faster than a GTX 650 1GB; costs only $144.5

Munch bunch: Still struggles at 1,920 x 1,080 with 4x AA

How much?

Typical street price: $149.99



AMD Radeon HD 7770 1GB

Like much of AMD’s current line-up, the HD 7770 1GB has received a healthy price cut recently, in addition to driver performance updates. Now available for around $149.99 for a stock card, it goes head to head with the GTX650 1GB; a card which, on paper, it comfortably beats.

The HD 7770 1GV uses AMD’s Cape Verde XT GPU. While it’s based around the same core architecture as its more auspicious siblings, Cape Verde is a significant reduction, with just a single front-end engine. This means that it sports just a single tessellation unit and rasterizer.

Ten CUs, each with four SIMDs, results in a total of 640 stream processors, alongside 40 texture units. This is almost a 40 per cent drop in the number of SPs from the HD 7850 2GB’s GPU, but the impact is lessened by an increase in core frequency, with a stock HD 7770 1GB running at 1GHz. The reduction in stream processors also sees Cape Verde XT’s 1.5 billion transistors squeezed onto a 123mm2 die, making for a maximum TDP of 80W. the card still requires a 6-pin PCI-E power connector though.

However, it’s hard to see a silver lining around the reduction in the number of ROPs to just 16, and the use of just two 64-bit memory controllers, resulting in a running a t1,125MHz (4.5GHZ effective), the HD 7770 1GB boasts just 72GB/sec of money bandwidth 8GB/sec lower than that of the GTX 650 1GB.

That said, the Unigine Heaven benchmark score of 691 clearly demonstrates the HD 7770 1GB’s advantage over the similarly priced GTX 650 1GB, and it also proved faster than the budget GeForce card in every benchmark. In Battlefield 3 at 1,920 x 1,080 with 4x AA, the HD 7770 1GB managed a minimum frame rate of 23fps compared to the GTX 650 1GB’s 20fps, although this is still below the playable barrier. Meanwhile, in Skyrim at the same resolution, the 7770 1GB was 25 per cent faster thanks to a minimum frame rate of 34fps. The HD 7770 1GB was more power-hungry, though, pulling a peak system load of 145W compared to the GTX 650 1GB’s 126W.


The HD 7770 1GB comprehensively outclasses the GTX 650 1GB which, thanks to AMD’s price cuts, is now its direct competitor. In all of our tests, the Radeon card proved quicker by a healthy margin, but as with the rest of the low-end cards, it still represents poor value for money compared the those that cost 50 per cent more. An HD 7850 2GB is 80 – 90 per cent faster in most circumstances and, while we recognize that you may be reluctant to spend more than $160.9 on a GPU, the benefits far outweigh the additional expense.

Scores: AMD HD 7770 1GB

  • 1920 speed: 7/20
  • 2560 speed: 5/20
  • 5760 speed: 1/5
  • Value: 45/55

Nvidia GeForce GTX 650 Ti 1GB

Fills a gap, but the HD 7850 2GB is worth the extra $40

Vip: Halfway point between mid-range and low-end; decent BF3 performance; playable frame rates at 1,920 x 1,080

Seat filler: HD 7850 2GB is a lot quicker and only $40 more expensive

How much?

Typical street price:$199.99



Nvidia GeForce GTX 650 Ti 1GB

With a $149.99 gap between Nvidia’s excellent GTX 660 2B and the low-end GTX 650 1GB; it’s no surprise to find the green team producing a middle-ground competitor. With prices starting at $199.99 for stock models, its price is certainly leaning more towards the low end of the market though.

The GTX 650 Ti 1GB’s GK106 GPU has made a number of cuts to enable the lower price. One of the card’s five SMs has been disabled, but this can be from any of the card’s three GPCs. While this can mean that some cards ship with an extra rasteriser (due to the higher GPC count), Nvidia tells us that performance is SM-limited, so there’s no difference.

Four SMs provide a healthy count of 768 stream processers, 64 texture units and four tessellation units as part of each SM’s polymorph engine. These figures are surprisingly beefy when you consider the $104.5 price difference between the GTX 650 Ti and the GTX 660. The former doesn’t benefit from GPU Boost, though, and uses a static stock core frequency of 925MHz.

Deeper cuts were made to the memory interface and ROP count. One of the GPU’s three 64-bit memory controllers has been disabled, dropping the memory interface to 28-bit and the ROP count to only 16 – just like the GTX 650 1GB. A stock memory clock of 1,350MHz (5.4GHz effective) makes for an effective memory bandwidth of just 86.4GB/sec.

As this card launched just before this issue went to press, we’ve only been able to test a $225 factory-overclocked SKU of the card; stock model will typical be around 10 per cent slower, so bear this in mind when looking at the performance figures.

The GTX 650 Ti’s Unigine score of 903 is a sizeable improvement over the HD 7770 1GB’s 691, with the GTX 650 Ti 1GB also boasting a substantial performance advantage is real-world games. In Skyrim at 1,920 x 1,080 with 8x AA, the GTX 650 Ti 1GB produced a minimum frame rate of 45fps compared to the HD 7770 1GB’s 34fps. However, the HD 7850 2GB, which costs just $32 more, offers a large step up, with a minimum frame rate of 53fos in the same test. Our factory-overclocked GTX 650 Ti also managed to comfortably produce playable minimum frame rates in out other test games at 1,920 x 1,080.


The GTX 650 Ti 1GB finds itself between two worlds. It’s certainly faster than the sub-$149.99 low-end cards, but also substantially slower than the mid-range delights of the HD 7850 2GB. It’s a GPU that’s been made to hit a price point, and while a $199.99  price may appeal to gamers on a budget, spending an extra $40 and grabbing an HD 7850 2GB is a far better decision.

Scores: Nvidia GTX 650 Ti

  • 1920 speed: 9/20
  • 2560 speed: 6/20
  • 5760 speed: 2/5
  • Value: 41/55