The CPU will throttle, as mumbling Steve demonstrates. However, if you got your rig to play video games, you should not notice any difference in performance.

If your machine has an Intel i9-12900 processor, and ...
a. It boots and works
b. Shows correctly in BIOS
c. Show correctly in Windows Device Manager

Then it is supported (obviously).

Lol ! Steve knows. 

I got my rig primarily for developing in Unreal Engine and other 3D Programs, as well as Video Editing.

I wasn't necessarily asking if it is supported, but thank you for replying anyway.  I'm asking if it is true that due to a lack of cooling, we are getting a performance equivalent to a lesser product. 

You might be interested in this discussion 

After I've been testing for a good bit, and complaining at the same time, the only throttling I get is with synthetic benchmarks.  That's where I am right now with it.

what would be an explanation for that result?

Power throttling.  It's not good for sure in that respect.   

As for gaming performance the machine works great, don't be gas lit. On the the web you may see certain benchmarks slightly lower that usual for timespy etc but this was due to early bios. I'm getting really good results in tests, memory, CPU GPU etc. Overclocking the GPU is easily done (3090)

For peace of mind for gaming look at the below article.

https://www.techpowerup.com/review/intel-core-i9-12900k-alder-lake-tested-at-various-power-limits/

You wont throttle in gaming, I steamed in OBS to test in slow mode, Warzone which already draws a lot of CPU power for a game and the machine performed amazingly well, the quality was great. You would use the GPU to encode your stream, which also was super good anyways. As a streaming machine its great, with no messing around in OBS which says a lot on the quality of the build, its rock solid.

Synthetic bench mark like Cinebench R23 on a ten minute run it will throttle, is it a game changer for me, definitely not. 

Will you see a performance hit on your software use in real time, it would be really interesting to know? 

Even a 360 rad when it's attached to a 12900 gets saturated, it will throttle, just go read the die hard posts on redit! 

. . . but why only with synthetic benchmarks? What about other CPU intensive operations?

What I meant by that is that I personally only see the throttling with synthetic benchmarks because I don't use it for other cpu intensive workloads.

I don't like that it does power throttle the way it does.  I don't like that we can't even enable XMP to get a bare minimum of 4800MHz ram speed.  There will probably be more issues in the future since the PSU is proprietary and they only offered the 750w PSU when I bought the system, then a few months later they started offering the 1000w PSU and they won't let me get one.

All in all, I won't buy from Dell again.  Hope that helps.

Don't want to knock on you, but that's a lot of money to put into a piece if equipment without researching it first. 

Some of the drawbacks of this system based on owner reports on this board:

- Not the best cooling performance.

- No XMP available for memory modules.

- OEM board, OEM power supply.

- The case, board and power supply do not confirm to any standard.

- AIO cooler is a 120 mm version and likely not the best option for the higher end CPU's, like yours.

- The CPU throttles under high CPU loads early on, I believe something like 50 seconds or so into a high CPU workload.

- If I am not mistaken the mounting studs for the AIO block is part of the case and therefore cannot be easily changed out or not changed out at all if you would want to put let's say a Noctua air cooler on it.

Basically, and there are multiple threads on this boards you can read up, the higher end configurations seem to suffer from reduced performance based on what the OEM (Alienware) choose for this line.

They do seem to perform well for gaming

The PSU is apparently a Gold 80 - the markings are on the side of the PSU as shown in the tear down vid

. . . but not ATX