I am curious why server grade boards are being considered “HEDT”. Never once have I seen a consumer be like, “you know, I need a motherboard that doesn’t fit into any case I own for my desktop.” The “D” and HEDT is Desktop, and these aren’t that.

bill1024
It’s an E-ATX board like most all EVGA Classified boards are. It should fit in a lot of medium cases and all full size cases.

Even my dual socket SuperMicro server boards fit in a full size case

Which case are you using and which motherboard? 
 
Like GamersNexus keeps saying, E-ATX doesn't actually make sense. Standard ATX is 9.6" x 12".  E-ATX as used means anything over 9.6" but most case manufacturers that I see have advertised E-ATX up to 11".  
 
The first time the classified boards were considered E-ATX was this generation, z690 and z790, prior to that they were all of their boards were ATX format or smaller, except for the Dark and HEDT format boards, and those boards were E-ATX up to 11".
 
EVGA Classified and most Dark (SR-3 being the one exception) boards are 10.895" x 12" E-ATX boards.  E-ATX means extended, but does NOT designate a size.  The SR-3 Dark and this board are E-ATX at 13"x12" The extra 2" of width would be covering some motherboard tray cable routing slots. It will fit in most Full Tower cases that have the extra supports to properly mount the end of the board, or it can be left unsupported, but it does not fit into a standard desktop case properly for 9" of users.  
 
Lets use my Caselabs TH10A as an example, because caselabs made massive cases (and will again since they are coming back under new ownership) and this is the X299 Dark mounted:
 

 
Now add an extra 2" to the motherboard, and it no longer fits properly in this massive case, it just covers all of the routing options, and means I would have to figure out how to run cables somewhere else.

 
 
The SuperMicro board is EEB format, at 13"x12" LianLi Even shows in their Odyssey X case that EEB boards fit, but completely block off any cable routing options, because the extra width is exactly where the "standard E-ATX" boards land at 11" or less. 

TRX80 boards are SSI EEB, so which consumer cases support SSIEEB?

TRX40 board came in SSI CEB/ATX sizes, so they fit into standard cases as well.

Also, who ever suggested that there shouldn’t be HEDT boards? I’m still on x299 because I want HEDT. X299 came in ITX, so saying HEDT can’t be in a smaller form factor is just a little close minded. Manufacturers could do like EVGA has an rotate the socket to fit 12 channels of memory in a North/South format rather than East West, and reduce the total number of PCI brackets available and then it could fit in a “E-ATX up to 11” wide.

Everybody needs a big case, for a big motherboard! Hopefully it is compatible with X13SWA-TF.