The next generation of Nvidia graphics cards has arrived. We first saw Nvidia's Maxwell architecture--the follow-up to Keplar--in the GTX 750 GPU. That $150 card was an entry-level introduction to Nvidia's new approach to desktop GPU design, incorporating power efficiencies learned from generations of Tegra development. From Loyd's GTX 750 review:
"Kepler has a monolithic control logic unit that managed scheduling for up to 192 cores. Maxwell now allocates a smaller, more efficient control logic unit for each block of 32 cores. This change in the scheduler, a larger L2 cache (2048MB versus 25K in the Kepler-based GTX 650) and a large number of smaller improvements allowed Nvidia to build 640 shader cores on a die, versus 384 on the GK107-based GTX 650."
More shaders, more transistors, and a larger die, all using less power than the last generation. That's what Maxwell now brings to the high-end, in the form of the just-announced GTX 980 and GTX 970 videocards ($550 and $330, respectively). They replace the GTX 780, GTX 780 Ti, and GTX 770.
GTX 980 has 2048 shader cores running at a base clock of 1126MHz (1216 MHz with GPU boost). But all that runs on a chip with a TDP of just 165 watts. That's compared to 250W on the GTX 780 and 195W on the GTX 680--the card that many users will be upgrading from, I suspect. The GTX 970, with 1664 CUDA cores, is even more power efficient at 145W TDP. We're talking about high-end GPUs that now only use two six-pin PCIe power connectors. SLI now starts to look a lot more attractive. And there's plenty of headroom for overclocking, if you're into that.
High-end Maxwell also brings three new features for gaming. First is a new anti-aliasing technology, called MFAA. Multi-frame sampled AA supposedly produces the effect of 4XMSAA with the performance hit of only 2XMSAA. Dynamic Super Resolution is a new feature that is essentially resolution downsampling--you can now tell the GPU to render games at 4K resolution for a 1080p screen. Screenshots and Shadowplay video recording spits out 4K resolution files in this mode, too. And finally, Nvidia is especially proud of a new lighting engine called Voxel Global Illumination. This is the first step in real-time light tracing, with fully dynamic illumination for one light source. Unreal Engine 4 will support VXGI in the fall, and Nvidia has produced a Apollo 11-themed render demo to show off the lighting feature.
Performance-wise, Nvidia is claiming 1.5 to 2X the performance of the GTX 680 (their choice for point of comparison) in the GTX 980. They're also claiming that the GTX 980 will be better for VR, with built-in optimizations to minimize rendering latency--taking 10ms out of OS overhead and built-in asynchronous warp. Nvidia is calling this VR support "VR Direct", and it's something I'll be asking Oculus about this Saturday at the Oculus Connect conference. As for real-world performance and evaluating Nvidia's claims, I'm getting a review unit in and will be testing it next week on my new Haswell-E system.