Pascal achieves even greater data transfers capabilities thanks to enhanced memory compression technology. Specifically, it builds on the delta color compression already found in today’s Maxwell-based graphics cards, which reduces memory bandwidth demands of grouping like colors together. Here’s how Nvidia’s whitepaper describes the technology:
“With delta color compression, the GPU calculates the differences between pixels in a block and stores the block as a set of reference pixels plus the delta values from the reference. If the deltas are small then only a few bits per pixel are needed. If the packed together result of reference values plus delta values is less than half the uncompressed storage size, then delta color compression succeeds and the data is stored at half size (2:1 compression).”
The new Pascal GPUs perform 2:1 delta color compression more effectively, and added 4:1 and 8:1 delta color compression for scenarios where the per-pixel color variation is minimal, such as a darkened night sky. Those are targets of opportunity, though, since the compression needs to be lossless. Gamers and developers would gripe if GeForce cards started screwing with image quality.
Using color compression to reduce memory needs isn’t new at all—AMD’s Radeon GPUs also do it—but Nvidia says that between this new, more effective form of compression and GDDR5X’s benefits, the GTX 1080 offers 1.7x the total effective memory bandwidth of the GTX 980. That’s not shabby at all, and it takes some of the sting out of the card’s lack of revolutionary high-bandwidth memory, which debuted in AMD’s Radeon Fury cards, albeit in capacities limited to 4GB.
The Pascal GPU’s technological enhancements and leap to 16nm FinFET also make it incredibly power efficient. Despite firmly outpunching a Titan X, the GTX 1080 sips only 180 watts of power over a single 8-pin power connector. By comparison, the GTX 980 Ti sucks 250W through 6-pin and 8-pin connectors, while the 275W Fury X uses a pair of 8-pin connectors. The GTX 1080 does a lot more performance with a lot less power.
The GTX 1080’s answer to AMD’s async compute
AMD’s Radeon cards hold an ace in the hole when it comes to games based on Microsoft’s radical new DirectX 12 graphics technology: asynchronous compute engines.
This dedicated hardware essentially allows multiple tasks to be run concurrently. The async shaders didn’t provide much of an advantage in DirectX 11 games, which run tasks in a largely linear fashion, but they can give certain DX12 titles a major performance boost, as you’ll see in our Ashes of the Singularity benchmark results later. And it can make a major difference in the asynchronous timewarp feature that the Oculus Rift VR headset uses to keep you from blowing chunks if there’s a hiccup in processing.
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