Looks interesting enough that I might have to get this and try it out.  Thought it was interesting enough that I'd share it here.

If I decide to take the plunge, I'll share my results.  If anyone else has already taken the plunge, I'd be interested in seeing your experiences with it so far.  This is a reasonably priced branch of the latest Blender releases, so it's not an addon.  I'd probably recommend using it solely for rendering purposes only, but it could probably accept most of your current addons if you wanted to use it as your primary tool.

They have a webpage, for those not inclined to watch the video.  THis is quite a leg-up on rendering time, if it works well with the hardware.

https://3dillusions.gumroad.com/l/turbo_tools

Will take a look as well looks interesting 

That certainly does look interesting, but since I haven't taken the plunge into Blender 3 yet, I'll wait and see, as the saying goes.

That certainly does look interesting, but since I haven't taken the plunge into Blender 3 yet, I'll wait and see, as the saying goes.

Ohhhh, now that I might look into for sure, as I'm starting to feel a bit more comfortable in 2.93, and where things are located in the new UI.

Update:  I just purchased this addon tonight and have played with it for an hour or so.  I'm still getting used to how to use it properly, although it is very easy to use out of the box.  There aren't many settings if you choose the presets, but there are still many things you can tweak by hand if you wish (which is what I've been doing).  So far, it's definitely handling large, complex scenes far better than anything else I've tried so far.  I'll show some examples when I get a chance, but since I'm trying to use it for animation purposes I'd like to render an animation with it before I show anything.  However, I also have K-Cycles, and so far this plugin has been able to render a 4k scene with heavy volumetrics and adaptive displacement in roughly half the time of K-Cycles, and triple as fast as vanilla Cycles, with better detail than using Optix denoiser.

One thing I would like to point out is that this is an actual ADDON, not a separate build like I originally suspected.  K-Cycles and E-Cycles are separate builds.  This is just an addon that you would install like any other addon to your existing build of Blender.  It uses a nifty node-cache system for composite nodes, so if you use process heavy nodes in composite, such as lens effects, this will cache the node results and reduce the render expense of such processing.   There are definitely some clever things going on.  My concern is animation, so the jury is still out on that until I can render a full animation with it, but for still images, it seems to be very fast and the results are extremely impressive.

Appreciate the follow up Lux.  I was considering purchasing the addon and your review has convinced me to go and do it.

One thing I noticed straight away.  It has its own denoiser built in somehow.  Make sure when you use it, you disable the render denoiser in Cycles.  If you don't do that, it may override them anyway, but I've been experimenting and so far noticed it may actually take extra time for it to do that.  Make sure you watch the videos showing the creator using the addon, because that helped me. I was a little confused as to why render times were exactly the same no matter what sample count I chose.  Come to find out the reason for that is because it will only consider your input samples when you use the "User" preset.  If you use the "low", "medium" or "high" presets, it overrides any of your manual values with preset internal values of its own.  So even if you have render samples set to 64, for example, it will not use that value unless you choose "user" preset.

Dang, that's very well-priced. If I continue to dig into Blender, I may well invest in that.

Keep in mind, folks, that Blender dev team will be integrating eCycles programming into CyclesX very soon.  In fact, you can actually download eCycles Lite for free now, since that will basically become a native part of Blender in future releases.  eCycles was previously a separate build of Blender that contained impressive rendering enhancements, and the Pro version still has some features that are not available in any other render addon.

However, in my most recent testing and experimentation, I've found the Turbo CyclesX addon actually outperformed eCycles Lite in many of my animations.  This primarily came from the ability to "clean" noise from a volumetric fog in an animation that I previously could not clean up with Optix or the OID node in eCycles Lite or regular CyclesX before.  This was the one thing that completely sold me on the Turbo CyclesX addon as a true solution for difficult-to-render animated scenes.  I had about two or three scenes that I had to put on the backburner for months, simply because I could not render them in a reasonable timeframe with the quality I wanted.  Thankfully, now I'm capable of rendering these scenes without a significant upgrade in hardware.