Nvidia
CEO Jen-Hsun Huang loves a spectacle. So while you’re reading this
sentence, the GPU-manufacturer’s founder is regaling thousands of gamers
at a 24-hour gaming event the company is sponsoring in Los Angeles with
the announcement of Nvidia’s latest graphics processor, code-named “Big
Maxwell.”
Despite Nvidia’s draconian efforts to prevent a recurrence of the leaks that presaged the announcement of its Shield Tablet,
details of the new GPUs have been dripping into the Interwebs for
several weeks. Here’s the official information: The new GPU will
initially be available in two SKUs, the $329 GeForce GTX 970 and the
$549 GeForce GTX 980. The GTX 970 has 1664 processor cores running at a
base frequency of 1050MHz (boost clock of 1178MHz), while the beefier
GTX 980 has 2048 cores running at 1126MHz (boost clock of 1216MHz). The
GTX 970 and the GTX 980 both have a 256-bit interface to 4GB of GDDR5
memory running at an effective speed of 7Gbps.
The
mounting brackets on cards following Nvidia’s reference design will
have one dual-link DVI connector, three DisplayPort 1.2 interfaces, and
one HDMI 2.0 port. HDMI 2.0 support is particularly important because it
supports 4K resolution at a refresh rate of 60Hz (the older HDMI 1.4b
standard is limited to a refresh rate of just 30Hz, which is fine for
movies, but terrible for games).
Dynamic
Super Resolution, according to Nvidia, enables the new GPUs to deliver
4K-quality graphics on a 1080p display. The processor effectively
renders 4K resolution in the GPU’s frame buffer, and then applies a
Gaussian filter to downsample the image to 1080p when it's output to the
monitor. This promises to increase visual fidelity without taking a hit
in frame rate. The feature is enabled by default in Nvidia’s GeForce
Experience utility, and the end user may increase the resolution as high
as 5K if desired. Scott Herkelman, general manager of Nvidia’s GeForce
business unit, demoed the effect for me at a briefing on Tuesday, and it
is impressive.
MSAA
works by having the GPU sample multiple locations of each pixel in a
scene, and then fully rendering and combining those pixels in the image
that’s ultimately rendered on the display. In 4X MSAA, four samples of
each pixel are taken. For all its effectiveness, MSAA is very
computationally expensive and can significantly reduce frame rate when
it’s enabled in a game. Nvidia’s Multi-Frame Anti-aliasing (MFAA) functions in a similar
fashion, but it samples pixels over two frames while rotating the
pixels. The technique, according to Nvidia, delivers results that are
very similar to MSAA without the performance hit that MSAA exacts.
Herkelman says MFAA is up to 30 percent faster than MSAA.
Voxel Global Illumination (VXGI) is the third big improvement to be
found in the GeForce GTX 970 and -980. Briefly, it’s a new lighting
technique that promises to deliver much better image quality without
requiring a significant performance hit. As Herkelman explained it, a
voxel (a portmanteau for volumetric pixel) stores information about the
light in a rendered environment.
Oculus Rift support
Nvidia’s VR Direct technology is intended to benefit upcoming virtual reality headsets such as the Oculus Rift.
This bundle of features is designed to reduce latency, allow headsets
to take full advantage of Nvidia’s dual-GPU SLI technology, and improve
stereo-vision support. Herkelman demoed a new space-combat game for me
Tuesday, and it looked leagues better than anything I saw over the
course of Nvidia’s 3D Vision initiative. Like the original Maxwell architecture
Nvidia announced in February, these new GPUs adopt power-savings tricks
originally developed by Nvidia’s Tegra CPU team. Where a GeForce GTX
680 card with 2GB of memory has a thermal design power (TDP) rating of
195 watts, and a GeForce GTX 780 with 3GB of memory has a TDP of 250
watts, the TDP for the GeForce GTX 980 with 4GB is just 165 watts. Despite
the lower power consumption, Nvidia says the GTX 980 will deliver 5
teraflops of single-precision compute performance, compared to 3- and
4TFLOPs for the GTX 680 and -780, respectively (a teraflop is one
trillion floating-point operations per second). The new GTX 970,
meanwhile, has a TDP of 145 watts and delivers 4TFLOPs of compute
performance. Thanks to the lower TDPs, reference-design cards will have
two 6-pin power connectors to supplement the power the cards draw from
the PCIe bus. In the wake of this product launch, Nvidia is discontinuing its
GeForce GTX 780Ti, GTX 780, and GTX 770. The suggested retail price for
basic boards based on its GeForce GTX 760 has been reduced to $219.