KitGuru tried the Gigabyte X99M-Gaming 5 mATX Motherboard
A quote from the article:
If you want to reduce the space taken up by your computer, without significant reduction in performance or functionality, opting for a micro ATX system has long been the most effective way of doing so. Can the performance of ATX parts be matched when the Gigabyte X99M-Gaming 5 motherboard's LGA 2011-3 socket is compressed into the 24.4 x 24.4 cm micro ATX form factor?Gigabyte X99M-Gaming 5 mATX Motherboard Review @ KitGuru