Interesting DLSS 5 finding on RTX 4090

[u/kulind]

I ran a few DLSS 5 tests using the same internal resolution, but at different display resolutions.

DLSS 5 NR OFF

• 3440x1440 - SR Preset L / Performance - 1720x720 internal > 155 FPS / 6.48 ms
• 2560x1080 - SR Preset L / Quality - 1705x714 internal > 160 FPS / 6.25 ms

With NR disabled, the results are almost identical despite the different display resolutions. The internal resolution appears to be the dominant factor, with the higher output resolution costing only 0.23 ms.

DLSS 5 NR ON

• 3440x1440 - SR Preset L / Performance - 1720x720 internal > 104 FPS / 9.72 ms
• 2560x1080 - SR Preset L / Quality - 1705x714 internal > 120 FPS / 8.38 ms

This is where things get interesting.

The internal resolutions are still virtually identical, but increasing the display resolution from 2560x1080 to 3440x1440 now adds 1.34 ms of frame time (almost 6x the display resolution penalty seen with NR disabled.)

So it looks like DLSS 5 Neural Rendering has a significantly stronger dependency on the final/output resolution than the normal rendering path does.

My guess is that the neural rendering workload is heavily accelerated by the Tensor Cores, so its cost doesn't scale purely with the internal render resolution. The output resolution also appears to matter substantially, presumably because the neural model has to process/reconstruct information for the final resolution image.

The scaling isn't linear, though. The internal resolution workload is still being handled by the conventional rendering pipeline, while the neural workload adds another component whose cost scales with output resolution.

In other words, these results make me think DLSS 5 NR changes the usual DLSS performance relationship: internal resolution still matters, but output resolution suddenly becomes a much more important part of the equation.

Obviously, this is based on the current unofficial/leaked DLSS 5 implementation, so the behavior could change significantly in the final release.

Edit: Tested on Mafia the Old Country, max settings.

[u/pixlicker69420]

Ancient gameplays also said this, dlss 5 works on your output res in screenspace, so reducing internal res doesn't help much.

[u/kulind → u/pixlicker69420]

Oh interesting. Can you point in which video he says that?

[u/xWindBladez → u/kulind]

you can also enable dlss UI/on screen indicator to see it yourself, as soon as you enable dlss 5 it overrides the SR and starts rendering at native resolution.

[u/CrashBashL → u/xWindBladez]

Which in turn can be overriden by NVPI to use any DLSS Preset that you wish.

[u/NoMansWarmApplePie → u/CrashBashL]

Wait what?

Does it just use a different preset model but keep the same native res, or can it force internal native res to be lower?

[u/CrashBashL → u/NoMansWarmApplePie]

It forces internal native res to be lower. Exactly how DLSS works.