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Power consumption

Over the last few pages, we've seen that the Radeon HD 8790M is much quicker than the 7690M. Now, we can see that performance increase doesn't come with substantially higher power consumption; the 8790M draws only 2W more under load. Not only that, but it draws less power than the 7690M at idle. Thanks to AMD's ZeroCore Power feature, which is exclusive to 28-nm, GCN-powered parts, power utilization falls even lower when the display goes to sleep.

Note that these numbers show power draw for the whole system, including the Core i7-3770K, which has a 77W power envelope. Total power use on a notebook would probably be much lower.

We would have included noise and temperature numbers, but the MXM GPU modules AMD sent us have very different cooling solutions, neither of which you can expect to see in actual notebooks. Noise and temperature measurements for these samples would be pointless at best and misleading at worst.

Conclusions
You know the saying: better late than never.

I think that applies to the Radeon HD 8000M series. Mid-range and low-end gaming notebooks have been saddled with 40-nm GPUs based on AMD's old TeraScale architecture for almost a year. The 8000M series finally rights that wrong by bringing 28-nm, GCN goodness to lower price tiers and power envelopes. AMD hasn't broken new ground here; it's simply made a year-old architecture available to more folks.

As our benchmarks have shown, the wait has been worth it. The Radeon HD 8790M beats the pants off its predecessor, and it does so while consuming less power at idle and only marginally more under load.

Before we sign off, we should remind readers that clock speeds and memory configurations will vary in the wild. So, not all of the 8790M or 7690M GPUs you find out there will be equivalent to those we tested. Some will feature slower DDR3 memory and may have lower core clock speeds, as well.TR

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