The first part of the model number
must start with X9. This is the CPU generation. E5-2600v1/v2 CPUs fall under this generation.
The next letter will be either S or D for
Single-CPU or
Dual-CPU. I'm assuming in
/r/homelab we all want the D
The next letter
must be an A or R. R means socket R, which is the same as LGA2011. A means workstation which as far as I can tell just means it includes onboard audio and video. You'll probably want to focus on the Rs for a server build.
That's it as far as requirements. A SuperMicro motherboard starting with X9DR supports dual E5-2600v1/v2 CPUs. The rest of the letters indicate features. Some notables letters, starting at the end of X9DR...
- L = "Low cost" models that skimp on features. This isn't going to do you much good on used boards from what I've dug up. Worth looking at but don't go seeking them out hoping for a much better deal.
- i or E = SATA controller only.
- 3 = SAS + SATA. Usually 8x SAS via 2x 8087 from what I've seen.
- 6 or 7= SAS2 and SAS2 6GB/s respectively.
- F = IPMI support. A must-have for me.
- LN4 = 4x ethernet ports. Make special note of this one because L and N can be used individually as well.
- + = Extra RAM support. In the case of the X9DR3, that's 24 sticks.
- -O and -B suffixes just mean retail or bulk.
The hyphen placement seems arbitrary from model to model. Most have the i/E/3/7 before the hyphen. L's have them after.
Those are the most important. Some models are more prevalent than others. X9DR3-LN4F+ is the common one which has 8 SAS, 6 SATA, 24 DIMM slots for a maximum of 1.5TB of RAM, 4x ethernet ports, and IPMI. The X9DR3-Fis the same thing with 16 DIMM slots and half the ethernet ports. If you punch X9DR into Ebay and sort by motherboards you'll get the results you're looking for. Add 3, 7, i, or E to start narrowing your search based on the type of storage controller you want.
Hopefully this will help someone who was in the same spot as me, confused as hell about LGA2011.