DLSS does the denoising since DLSS 1.0 see the DLSS announcement https://www.youtube.com/live/4_g_Y0W1Xn8?feature=share (pardon the crappy gaming channel, it looks like Nvidia weren’t running their own YouTube the time)
There may be some confusion between upscaling and denoising. You might notice I keep editing my comment because it’s really really hard to find old Nvidia release announcements.
Update: https://youtu.be/6O2B9BZiZjQ looks good around 3:54 Nvidia refer to “deep learning for image denoising” which to me seems like DLSS.
Ray tracing without DLSS might be a different denoising technique. Is it really slow when you turn it on ?
It adds frames since I think 3.0.