No, 9th gen HEDT (anything starting with a 9, e.g. 9800x, to 9880xe) is not supported on the 51 R4.

It only supports Skylake X, so anything from 7800x up to i9-7980xe.

Yes, it does support an i9, the 7980xe is an i9. 

And yes. It can run RTX cards.  Turing and ampere.  Keep in mind size and PSU requirements as they vary by make/model.

Appreciate the reply. I picked up a 7820X for cheap, so Im gonna get the machine running with that. 

Any limitations for the NVMe drive? 

I'm not aware of any compatibility issues with the WD nvme drive that you mentioned. 1TB options aren't much more than 512gb these days, so you might consider upping the size. The R4s shipped stock with OEM samsung nvme drives, similar to the 970 evo plus on amazon.

https://www.dell.com/support/home/en-us/product-support/product/alienware-area51-r4/docs

Yea I'll probably step it up. My biggest concern was the Bios being not up to date to accept the newer CPUs, so I figured get the older one I know should work, update, and then possibly try something else. 

I know the R8 I have can be picky with RAM so I'm sure this one will be too. 

Appreciate the help. I'll def be updating the situation and process as it goes along. 

So I received the computer today. As expected, it has the OHJ5Y7 mobo in it.

The CPU socket cover shows its LGA 2011-3.

I was told by the seller that this PC ran an LGA 2066 CPU - the i7 7820X.

A quick search shows its the same mounting solution and the 2066 is backwards compatible. Just spooked by the socket cover I guess. 

So the question is, am I going to run into any issues with the i7 7820X in this computer? Did they even offer the older CPU in initial configuration for the R4?

Thanks.

"The CPU socket cover shows its LGA 2011-3.

I was told by the seller that this PC ran an LGA 2066 CPU - the i7 7820X."

The Area 51 R4 is X299 (on LGA 2066 socket).  

If you're referring to a piece of black plastic that shipped covering the motherboard socket, that's just something that was added (possibly by the seller or supplier) to protect the pins from getting bent during shipping. 

It was sold stock with Skylake X, 7000 series HEDT CPUs (and only 7000 series CPUs).  

The R5 got the bios update to support the 9000 series. 

It should work, but there might be a hick up. They normally install OEM versions of these CPU's in the systems. If you use a retail CPU you would expect it to equally work, but there's a chance it might not boot due to unrecognized CPU.

 That would be horrible. Fingers crossed then. 

"That would be horrible. Fingers crossed then." 

Yeah, I wouldn't worry about it much though.  The Intel microcode for tray and retail processors is generally the same, to the extent of a difference you would expect it to be based on manufacturing date, not retail vs tray status.   For example, earlier revisions of the i3-9300 are supported with 8th gen code; so some but not all 9300s can work in the Aurora R7, even though the R7 never got Intel 9th gen bios update). In other words you'd expect more support, not less support, in this case for the R4. Where you would expect real issues is with an ES version of a CPU (which technically are not legally resold though you still find them on ebay).

Update. Got everything working except the Alienware command center. I may have messed it up because I started it all up with a newer Alienware Mouse and now can only change the RGB on that. I can't change the colors of the case. A little frustrating. 

Do you know what version of AWCC I need to run the case lights? The latest version will not show any compatible AWCC components connected. Or maybe I'm missing a driver from the clean install or something. Also, I ended up going with the R5 mobo.