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Update: Taking AMD To Task On Enduro

Xotic PC NP9150: Striking Back At Kepler With Radeon HD 7970M
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I’ll be the first to admit that it’s difficult to keep up with everything that goes on in technology. While our eyes are turned to the latest tablet, a new SSD, or an upcoming processor, a bit of news surfaces, causes a brief stir, and disappears again. For anyone affected, a misbehaving piece of hardware remains a thorn that everyone is expected to be aware of. So, we understand the frustration when a vendor is allowed to get away with slow support for a high-end (expensive) component.

In the case of AMD’s Radeon HD 7970M, GPU underutilization issues were simply something we hadn’t seen before. They certainly didn’t hamper Thomas in today’s story.

But what you should expect out of us is that, when an issue does come up, we’ll be on top of it. And when readers started linking to forum posts about a problem with AMD’s newest flagship and its Enduro switching technology, we jumped.

On a phone call with company representatives earlier today, AMD admitted that its current implementation is indeed affected by a driver bug that prevents the hardware from being fed data fast enough, causing it to go underutilized, particularly at high frame rates. This is specific to Enduro-equipped configurations because the Radeon GPU is operating through integrated graphics, utilizing the PCI Express bus as a display engine. As a result, there’s a balance issue between data coming in and data going out you wouldn’t see from a notebook equipped only with discrete graphics.

Alienware’s M17x can be made to work around this problem. How? The notebook has a hardware-based multiplexer that, after a reboot, can turn off Enduro and make the Radeon HD 7970M a standalone GPU.

Why didn’t the issue come up in our story to begin with? Two reasons. First, if you look at our gaming benchmark results, there are only a couple of instances where the Radeon HD 7970M doesn’t scale quite as we’d expect, and those are in games already known to be fairly platform-bound. This could have easily been attributed to the Core i7-3820QM. Second, by AMD’s own admission, the degree of underutilization is most pronounced at low resolutions and high frame rates, but can affect frame rates from anywhere between 10 to 35%. Our emphasis is on higher resolutions and more demanding settings.

Now, what’s being done on AMD’s part to fix all of this?

According to the company, it has a hotfix that will go live first—purportedly in October. I’m working to get readers access to an early build earlier than that, but AMD is naturally apprehensive about the potential support ramifications of this. Representatives claim that the fixed driver will alleviate the bottleneck entirely, and the only performance hit you’ll be able to measure will be the expected 1 to 5% attributable to going through integrated graphics.

So, there we have it. An issue does exist, AMD is aware of it, a fix should be showing up in less than a month that rectifies the bug, and we’re working to get you early access. Of course, as we see in the benchmarks, even with the bug affecting performance, AMD’s Radeon HD 7970M has little trouble distinguishing itself.

And by the way, if you’re encountering weak performance on a 64-player map in Battlefield 3, consider that the workload is more CPU-bound than anything, and that a stock-clocked mobile processor is probably your weak point, not the GPU. We do read the comments, after all. ;)

Cheers,
Chris Angelini

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