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Zacate: Power And Heat

AMD Fusion: Brazos Gets Previewed: Part 2, Performance

AMD is trying to make a point that it has power management figured out. Comparing the E-350 APU to the company's current Nile platform (K625 + 880G), there are clearly some serious improvements being touted through the Zacate part.

As far as we're concerned, the component level is less important than total platform power. Of course, we're interested in the power consumption of a mobile platform because that helps determine the amount of time we can spend away from a wall socket.

We crunched some numbers, and based on our typical use system power numbers, the E-350 comes in at 18.6 W. This is with the system's wireless adapter active, 12.1" LED LCD set at 100 nits, and utilizing Windows' Balanced setting. How does this compare to other similar CULV notebooks? Well, thankfully, we had two examples from Asus to put things in perspective.

The 1215N (Atom D525/Ion 2) and the 1215T (Athlon II Neo K125/Mobility Radeon HD 4225) are both 12.1" LCD CULV notebooks, and they're probably the most popular in the company's eeePC line. Arguably, this form factor has also been called "the premium netbook" and we don't necessarily disagree. But this is definitely part of the CULV notebook group that AMD is vectoring towards with Zacate.

AMD's demo platform didn't have a battery connection, so we had to rig up a Electrovaya PowerPad to measure DC wattage. In our typical use scenario (IE8 Web surfing), the E-350 falls behind the previous K125 and D525/Ion2 platform. AMD tells us it is still working on closing that gap. As this is a preproduction sample, we probably can expect upwards of 10-15% power savings on top of the 18 W. Based on our use, it seems that AMD may see the biggest power savings by playing with the GPU. At the moment, it seems to be operating at max clocks all of the time.

Heat is a more intesting story, as we took the picture above while the systems were idling. It is hard to draw a definitive statement based on these pictures, because we are looking at different PCB real estate, heatsink material, heatsink size, and so on. In order to look at things more closely, we took the following pictures of the processors unshielded roughly ~45 seconds after booting.

Even though the E-350 has a higher thermal footprint per area, that is understandable, given the fact that Intel's D525 doesn't have a powerful graphics core. Moreover, you would actually need to double the thermal footprint per area of the D525 if you took Nvidia's Ion2 chipset into account.

For a CULV notebook, we don't hesitate to say that AMD has an amazing design given the lower proportional heat emissions. However, measured power consumption is still something to keep an eye on. At 18 W, the E-350 still consumes more power than what we would like to see from an AMD-based ULV processor.

In our preliminary tests, the Asus 1215N and the 1215T have similar battery life, but they get there via different approaches. The 1215N employs Nvidia's Optimus technology, which means that, at idle, its power consumption is similar to a vanilla Intel system. Meanwhile, even though the K125 is still a power hog, it has the driver support to dial back the IGP's clock rate.

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