This is because Blender is in fact using CUDA?

Blender supports CUDA, HIP, OneAPI, and Metal. So Intel GPUs are performing poorly using their native API.

The key feature on intel platforms is the hardware de-noise acceleration (NVIDIA OptiX also works well.) Note, AMD OpenCL works quite well for some renderings, but blender flamenco likes consistent cluster hardware.

For 8k HDR10 media or 3+ screens the rtx 5090 32G model is going to be the minimum card people should buy. Just because you see 4 DP ports, doesn't mean the card can push bit-rates needed to fill an HDR10 display >60Hz.

The Mac Studio Pro unified >512GB ram/vram is a better LLM lab solution (Apple recently NERF'd it to 256GB.) Who cares if a task completes a bit slower, it doesn't matter given the lower error rates... and not costing $14k like an rtx 6000. =3

Great tutorial on getting blender to behave on mid-grade PC and laptops etc. :

https://www.youtube.com/watch?v=a0GW8Na5CIE