E-ATX standard? (subtitle, break out the drill and 6-32 tap)

number9
Fri, 01 Aug 2025 04:42:22 -0500

It has been quite a while since I had to purchase and build a server computer from scratch. As it turns out, we had a need at work for a server motherboard in a desktop case. No big deal, I have literally built 1000s of computers in my lifetime....
Lets get some parts
The mobo decision was driven by needs and was easy enough. Past experience with Supermicro has been very positive, and a dual socket xeon board that had enough slots was within budget.. Pulled the trigger on a X11DPi-n, and got a few 20 core Xeon SP processors. Power supply was a Thermaltake 1500W, and storage was some Samsung Nvme drives. The case... well, orderd a Lian Li. Out of stock. Ordered another Lian Li, out of stock. Finally found an in stock Lian Li. Got it. (the reason behind the Lian Li was prior experience and support for EATX and large PCI-E cards).
The case and lets put it together
So far so good... it mostly all comes in, well, missing the CPU but hey, we can build it and wait. The cases are (at first glance) amazing. The ones I purchased are the O11 Dynamic EVO and they are bad-ass. I do not have many quams with this case, and full disclosure I own two Lian Li all aluminum tower cases from the late 90s that I just adore. The case is well thought out, does involve a bit of decision making about where to put drives or the PS (not that it is a bad thing, it is a good thing it is just that the user has a lot of options). However, after installing the PS I moved onto the mobo and...

The mother-f mounting holes do not line up. To be specific, two of them at the expansion slots do, and nothing else does. No pre-drilled holes in the mounting plate, mounting plate is not long enough for an E-ATX, nothing. WTF. Read the manual, nothing. Go back to the site, yes, Lian Li says E-ATX. Huh. STFW, yup, a lot of sites note that there is no real E-ATX standard, and companies can put mounting holes anywhere they want, basically... caveat emptor. Note, I do not think this is Lian Lis fault, this is a case of SuperMicro can call anything E-ATX as long as it is so wide and so long. Ah well, the case is great... time to break out the No. 36 drill bit and tap that back plate to 6-32.