How can i improve rendering time in After effects 2022

Render times depend on what is going on in your composition. Most professionals never have more than one shot in a single composition. Three minutes is an incredibly long shot. I am guessing that you are using After Effects to edit a movie instead of creat shots for a film.

If a project is incredibly slow to render, it is almost always more efficient to render a production master using the Render Queue. The rendered shots are usually edited using Premiere Pro. If you want to distribute a rendered shot, add it directly to the Media Encoder to render an H.264 MP4 using one of the standard templates. Fiddling with the knobs can dramatically increase render times and reduce the quality when YouTube, Vimeo, or other social media platforms re-compress your video for streaming. They all have standards, and if you submit something that doesn't fit the re-compression for streaming will always reduce the quality of the product viewers will see.

The Media Encoder opens a copy of After Effects in the background, reducing system resources.  If you Close AE after the AME opens, render times will improve. I believe that the Media Encoder can still not use all of the rendering acceleration available in the Render Queue. The Render Queue is not designed to render MP4 distribution copies of your comp. It is intended to render lossless frame-based production masters for editing or as Digital Intermediates for further production. Final editing is usually done in an editing app like Premiere Pro. Editing apps are capable of rendering distribution copies as well as production masters. 

I hope this helps. Just one shot with render-heavy effects can slow down or even cause a 3-minute long render to fail.  Unless a comp contains a transition that cannot be created in an NLE my comps are always only one shot long and only a few of them are longer than seven seconds.

Aside from what the others said, it doesn't really just come down to the actual encoding. You could have a single slow effect or expression in your project and then none of this matters. Either way, as the others already said you have to be much more specific and provide info about your system, the project contents, exact settings everywhere and so on.

Mylenium

The Mercury Software vs. CUDA dropdown in Media Encoder doesn't have as much bearing as you might think in this case. As Jake said, letting us know your PC specs will definitely help influence suggestions, but here is what I would do:

1) Leave Multi-Frame Rendering enabled.

2) See if Mercury GPU acceleration is enabled in your After Effects project (File > Project Settings > Video Rendering and Effects tab).

3) Export to something other than a highly compressed format like H.264. 

If you export a ProRes 422 file to your SSD then I bet it will export much, much faster than the H.264. Unless you need to work in After Effects at the same time, you can save yourself a little hassle but exporting this file directly from the Render Queue. You can then convert this ProRes file to H.264 in AME.

Rendering your frames and compressing them to H.264 in the same step while also highly compressing them with a low bit rate will always require significantly more processing power than rendering to an intermediate codec like ProRes. For good measure, you can compare rendering the same file to ProRes on your SSD and your HDD, but make sure you clear your Preview and Disk Cache before the second render so you get accurate results, otherwise your second render will be super fast since AE already rendered those frames.

Please tell us your PC specs. It all boils down to that.

I'd recommend clearing disk cache, allocating as much memory as possible to ME, make sure "Cache Frames when Idle" is off (Composition > Preview)