from Hacker News

CUDA Ray Tracing 2x Faster Than RTX: My CUDA Ray Tracing Journey

by ibobev on 6/25/25, 9:42 PM with 14 comments

• by E-Reverance on 6/25/25, 11:58 PM

  See comments as to why this is misleading https://www.reddit.com/r/GraphicsProgramming/comments/1ljmf0...

• by esperent on 6/26/25, 6:23 AM

  I think the title of this should be changed, at the moment it's click bait. It should be something like:

  CUDA Ray Tracing 2x Faster Than RTX when Rendering Spheres

  As far as I can see, this renderer can't do anything else except spheres (and maybe planes).

  It's no bad achievement to beat a general purpose production renderer at one specific thing, but a renderer that can only do spheres is just a hyper-optimized toy, and here it's being presented as far more than that.

• by sheepscreek on 6/25/25, 10:47 PM

  I’m guessing it’s because they’re using all the computing power the GPU has to offer in CUDA mode, as opposed to sharing the GPU with other functions (when in RTX).

• by kachapopopow on 6/26/25, 6:16 AM

  wow, bypassing a rendering backend makes things go faster, what a surprise!

  This only runs on nvidia, vulkan is designed to be cross-compatible with not only gpus, but operating systems as well. Vulkan is pretty direct compared to something like dx11 thought so I guess it is interesting to see performance improvement non the less.

• by kookamamie on 6/26/25, 7:20 AM

  > __restrict__ Pointers

  Ahh, my favorite nitpick from C++ not having sane default aliasing rules spills to the CUDA-land.

• by pixelpoet on 6/26/25, 5:40 AM

  > FMA performance here is a non-issue, I'm not just flexing—I'm showing off my CUDA prowess. But hey, got to demonstrate I know my hardware!

  This article is pretty embarrassing, and as others have noted, very misleading due to the RTX units hardly being used.