rendu graphique long

When you're using Dynamic Link it's really going to depend on what the content is and how optimized that is over in After Effects. You're basically opening a background version of After Effects and are processing full frames of whatever is built over there, and that can be quite complex. You can have AE projects that take several minutes per frame to process. It could be using effects that are constrainted to the CPU or single-threaded, which could create a bit of a hardware bottleneck. But it's hard to be able to answer any more thoroughly than that without better understanding what this mogrt or dynamically linked comp is. They can be convenient, but aren't necessarily fast.

Edit: You added the link to the mogrt in your other post. Thank you. Probably depends on which title you are using but some of those may be using methods that can be a bit slow to process. You can also try opening these MOGRTs up in After Effects and rendering directly out of there to see if it goes any better.

What effects are applied to it?