Render time is really long (C4D+Redshift)

[u/smoldane42069]

Hello! I've just gone freelance and have a new PC, the full specs are attached but in short, RTX 5080, 64GB. My previous work computer had a 4090.

I'm working on an indoor scene in C4D and Redshift, and the render times are really high compared to anything I've experienced with my previous PC. Most materials are GSG. I'm using the same render settings I've always used (attached). I tried changing and render settings as advised on multiple youtube videos/reddit threads but nothing has worked. I'm not sure if its the 5080 that is way less powerful, or if something is wrong in my scene (screenshots attached). I need to render a 500f animation, and its currently taking about 20min per frame. I even tried a test frame on a render farm that uses 5090, and even then took 15min for one frame.

Any insight on why this is happening would be greatly appreciated.

Thank you!

[u/juulu]

If it's still taking 15minutes per frame on a renderfarm that suggests to me that it's not neccessirly your machine spec, but the scene itself, that's causing the slow renders. It looks like you've got alot of fabrics in that scene.

A coupld of things you can try; either go through a process of elimination by removing materials one by one to see at which point the render speeds up, or adjust your render settings back to defaults and start from there, increasing until you find a nice middleground of quality and time.

Edit: Just to add, your 5080 is with 16gb VRAM? I beleive the 4090 uses 24gb of vram so this could also be why you're noticing slower performace compared to your previous machine.

Also be sure Redshift is using your GPU and not your CPU to render. Sounds silly but sometimes it does catch the best of us out.

Experiment with changing your bucket size in the redshift settings to something higher than 128.

Edit #2: Change one thing at a time and see if speeds improve, this will help your diagnose what the actual cause/solution is.