During this week, each GDC (the Game Developers’ Conference) and GTC (the Game Technology Conference) are happing in California, and NVIDIA is out in pressure. The firm’s marquee gaming-related announcement right this moment is that, as many have been anticipating would occur, NVIDIA is bringing DirectX 12 DXR raytracing assist to the corporate’s GeForce 10 collection and GeForce 16 collection playing cards.
When Microsoft first introduced the DirectX Raytracing API simply over a yr in the past, they set out a plan for primarily two tiers of {hardware}. The forward-looking plan (and long-term purpose) was to get producers to implement {hardware} options to speed up raytracing. However within the shorter time period, and owing to the truth that the API would not say how ray tracing ought to be carried out, DXR would additionally enable for software program (compute shader) primarily based options for GPUs that lack full {hardware} acceleration. In truth, Microsoft had been utilizing their very own internally-developed fallback layer to permit them to develop the API and check in opposition to it internally, however previous that they left it as much as {hardware} distributors in the event that they wished to develop their very own mechanisms for supporting DXR on pre-raytracing GPUs.
NVIDIA for his or her half has determined to go forward with this, saying that they may assist DXR on a lot of their GeForce 10 (Pascal) and GeForce 16 (Turing GTX) collection video playing cards. Specifically, the GeForce GTX 1060 6GB and better, in addition to the brand new GTX 1660 collection video playing cards.
Now, as you would possibly count on, raytracing efficiency on these playing cards goes to be a lot (a lot) slower than it’s on NVIDIA’s RTX collection playing cards, all of which have {hardware} raytracing assist through NVIDIA’s RTX backend. NVIDIA’s official numbers are that the RTX playing cards are 2-3x quicker than the GTX playing cards, nonetheless that is going to be workload-dependent. Ultimately it is the sport and the settings used that may decide simply how a lot of an extra workload raytracing will place on a GTX card.
The inclusion of DXR assist on these playing cards is purposeful – that’s to say, its inclusion is not merely for baseline featureset compatibility, ala FP64 assist on these similar components – however it’s very a lot in a decrease league when it comes to efficiency. And given simply how performance-intensive raytracing is on RTX playing cards, it stays to be seen simply how helpful the function will probably be on playing cards missing the RTX {hardware}. Scaling down picture high quality will assist to stabilize efficiency, for instance, however then at that time will the picture high quality good points be price it?
Under the hood, NVIDIA is implementing assist for DXR through compute shaders run on the CUDA cores. In this space the current GeForce GTX 16 collection playing cards, that are primarily based on the Turing structure sans RTX {hardware}, have a small leg up. Turing contains separate INT32 cores (quite than tying them to the FP32 cores), so like different compute shader workloads on these playing cards, it is attainable to choose up some efficiency by concurrently executing FP32 and INT32 directions. It will not make up for the dearth of RTX {hardware}, however it no less than offers the current playing cards an additional push. Otherwise, Pascal playing cards would be the slowest on this respect, as their compute shader-based path has the very best overhead of all of those options.
This listing of playing cards contains cell equivalents
One attention-grabbing facet impact is that as a result of DXR assist is dealt with on the driver stage, the addition of DXR assist is meant to be clear to present DXR-enabled video games. That means builders will not have to difficulty updates to get DXR engaged on these GTX playing cards. However it goes with out saying that due to the efficiency variations, they possible will need to anyhow, if solely to supply settings appropriate for video playing cards missing raytracing {hardware}.
NVIDIA’s personal steerage is that GTX playing cards ought to count on to run low-quality results. Users/builders will even need to keep away from the most expensive results comparable to international illumination, and persist with “cheaper” results like material-specfic reflections.
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