Many of the HD 7770's new features won't be noticeable right away. The underlying architecture is a big step forward for AMD that programmers and developers will find attractive, but for gamers looking to get playable frame rates out of DX11 games at 1080p its benefits aren't as obvious.
We're expecting the HD 7770 to enter at around the £100 point, which means it's going up against Nvidia's 550 Ti. While we didn't see it outperform the Nvidia card by the 100% AMD implied, it does hold a clear performance advantage, in addition to the subtler features under its bonnet.
Our sticking point though is that it was outclassed in every benchmark we ran by the previous generations' darling; the HD 6850. With just £20 difference between the two cards, we'd have liked to have seen a closer battle between the two.
It's worth mentioning that AMD's drivers tend to get better results from any given card after a few months of refinement, so further down the line we might see more parity in the benchmark figures between the two cards.
As with the HD 7750, the HD 7770 didn't impress in its overclocking performance the way AMD's high-end HD 7970 did. That £440 card maxed out AMD's overclocking software settings before crashing; the same can't be said here.
We managed to add on another 50 MHz to the core and memory clocks which yielded a modest increase in our benchmark tests, but it wasn't a reliable runner with those settings - glitches and crashes kicked in after a few minutes. Hopefully we'll see the full extent of the HD 7770's potential when the third party manufacturers release their beefed-up versions.
The 7-series might not all deliver staggering performance and overclocking, and that's to be expected given their wildly different pricings, but there is one feature that consistently impresses across the range - ZeroCore.
This is power-efficiency taken to a happy extreme – when your system enters a long-idle state, the HD 7700 along with all 7-series cards completely powers down the fan, 3D engine, compute units, shaders – virtually the whole card. The only activity going on comes from a small bus control block, which simply lets your computer know that the card still exists and no-one stole the GPU while it's been asleep.
We found it to be fast-acting, and dramatically reduced power draw when our system went idle.
This HD 7770 brings AMD's new architectural features to the budget audience with reasonable success.
Its GCN design and ZeroCore power efficiency make it a compelling argument to choose new over old, but it doesn't quite blow the best of the 6-series cards out of the water in plain old gaming performance.
The HD 6850 can't do the 7-series cards' tricks, but it can render Metro 2033 frames quicker, and that makes the HD 7770 a tricky one to recommend.
As a stock card, it doesn't offer anything outstanding, but aftermarket companies might yet yield some impressive performances out of it.
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