$100 shipped to the US via Priority Mail.
Significantly slower cores, but twice as many of them.
The big question is if they are compatible with the motherboard in my Dell Precision T5810 computer that is currently running the E5-1650 v4 CPU. As far as I can tell, they use the same FCLGA2011-3 socket, but I'm having trouble finding any definite info about BIOS compatibility on those computers...
I've run them in an ASUS Z10PC-D8/SAS and a Supermicro X10DRL-i. I'm confident that they should work in pretty much any aftermarket 2011-3 board, since the 2680v3 on which the 2678v3 is based had BIOS support from day one afaik. I'm not even sure if there is any difference at all from the 2680v3, they have the same base frequency, Turbo map and TDP.
If a compatible motherboard could be had for something like $170 + $104 gets you 8x4GB ECC DDR4 on eBay(though a decision would have to be made between 32GB total or 64GB total depending on budget) + your processors for $100 + $20 120GB SSD + cheap case + on sale power supply somebody could put together a 48 thread really good crunching machine for under $600.
I'm all on board with Ryzen stuff, but I really do like the extra thread count of the older Haswell Xeon stuff even if it's slower or less efficient than Ryzen. My 56 thread Xeon machines(I have 2 of them) are super easy to bunker on between the high thread count and slower task times, and still just churn out a really good amount of work it seems like.
@Fardringle is your machine single socket?
I do think I'd like to get one of those CPUs if you're willing to split them up. I actually have two of these computers, but one of them is sometimes used for gaming and other things by my girls, so the faster single core speed of the current CPU is a better option for that machine.
Unless Icecold wants to take both of them, and then I say go for that so they can both be put to good use.