Nvidia just released its latest 451.48 drivers for Windows PCs. These are the first fully-certified DirectX 12 Ultimate drivers, but they also add support for WDDM 2.7—that's Windows Display Driver Model 2.7. New to Windows 10 with the May 2020 update, and now supported with Nvidia's drivers, is hardware scheduling. This new feature shows up in the Windows display settings, at the bottom under the Graphics Settings, provided you have a Pascal or later generation Nvidia GPU. Could this help the best graphics cards perform even better and maybe shake up the GPU hierarchy? Probably not, but we decided to find out with empirical testing.
First, it's important to note that this is not a new hardware feature but rather a new API feature. GPUs, at least as far as we understand things, have been able to support GPU hardware scheduling for some time. The description from Microsoft is vague as well.
Enabling the feature is simple. In the Windows Settings section, under Display, you can click "Graphics settings" to find the toggle. It says, "Reduce latency and improve performance. You'll need to restart your PC to have your changes take effect."
Information circulating on the web suggests GPU hardware scheduling could be quite useful, but we decided to investigate further. We selected five games out of our current GPU test suite, then ran benchmarks with and without hardware-accelerated GPU scheduling enabled on a few test configurations. We used an RTX 2080 Ti as the main test GPU, and ran the benchmarks with both Core i9-9900K and Ryzen 9 3900X. Thinking perhaps a low-end GPU might benefit more, we also went to the other extreme and tested a GTX 1050 card with the 9900K.
Obviously there are a ton of potential combinations, but this should be enough to at least get us started. We also tested with every possible API on each game, just for good measure. All testing was conducted at 1920x1080 with ultra settings, except for Red Dead Redemption 2 on the GTX 1050—it had to use 'medium' settings to run on the 2GB card. We ran each test multiple times, discarding the first run and then selecting the best result of the remaining two runs (after confirming performance was similar, and it was).
Spoiler alert: the results of GPU hardware scheduling are mixed and mostly much ado about nothing, at least in our tests. Here are the results, with charts, because we all love pretty graphs.
Borderlands 3 showed a modest increase in minimum fps on the RTX 2080 Ti using the DirectX 12 (DX12) API, while performance under DX11 was basically unchanged. The Ryzen 9 3900X showed improved performance with both APIs, of around 2%—measurable, but not really noticeable. The GTX 1050 meanwhile performed worse with hardware scheduling (HWS) enabled, regardless of API. The lack of a clear pattern is going to be the only 'pattern' it seems.
The Division 2 basically flips things around from Borderlands 3. Hardware scheduling resulted in reduced performance for both the 9900K and 3900X under DX12, and made little to no difference with DX11. Meanwhile, the GTX 1050 shows a very slight improvement with hardware scheduling, but not enough to really matter—it's about 3% faster, but at sub-30 fps.
Forza Horizon 4 simplifies things a bit, since it only supports the DirectX 12 API. This time, we measured very slight improvements with the 3900X and a bit larger boost with the GTX 1050, while the 9900K with 2080 Ti had basically the same performance.
Metro Exodus kicks things up a notch with DirectX Raytracing (DXR) support on RTX cards, giving us yet another comparison point. Hardware scheduling gave a negligible performance increase on the 9900K, with DX11 performing slightly better than DX12. DX11 also performed better with the 3900X, and this time hardware scheduling reduced performance just a hair under DX12. For DXR, however, the results are mixed: higher minimum fps on the 9900K with lower average fps, and lower performance overall with the 3900X. As noted earlier, there's no real rhyme or reason here. The GTX 1050 meanwhile showed no change in DX11 performance, while it got a 4% boost (but at less than 14 fps) under DX12.
Finally, we have Red Dead Redemption 2, running under the Vulkan and DX12 APIs. Performance was universally better with Vulkan, as shown in the above chart. Hardware scheduling meanwhile gave a slight boost in performance on the 9900K, and a larger 5% boost to average framerates with the 3900X. 99th percentile fps on the 3900X only improved by 2%, however, so while hardware scheduling helped, it's not quite in the expected fashion—i.e. better minimum fps. The GTX 1050 showed slightly worse performance with hardware scheduling this time.
Initial Thoughts on Hardware Scheduling
What to make of all of this, then? Nvidia now supports a feature that can potentially improve its performance in some games. Except, it seems just as likely to hurt performance as well. This is a new API and driver feature, however, so perhaps it will prove more beneficial over time. Or perhaps I should have dug out a slower CPU or disabled some cores and threads. I'll leave that testing for someone else for now.
At present, across five tested games using multiple APIs, on average (looking at all nine or ten tests), the change in performance is basically nothing. The 9900K with RTX 2080 Ti performance is 0.03% slower, and the GTX 1050 with the 9900K performed 0.73% slower. The 3900X with RTX 2080 Ti did benefit, but only to the tune of 0.06%. In other words, the one or two cases where performance did improve are cancelled out by performance losses in other games.
If you're serious about squeezing out every last bit of performance possible, maybe for a benchmark record, you can try enabling or disabling the feature to see which performs best for the specific test(s) you're running. For most people, however, it appears to be a wash. Your time will be better spent playing games than trying to figure out when you should enable or disable hardware scheduling—and rebooting your PC between changes.
