https://wccftech.com/asrock-x299-motherboards-to-feature-up-to-2-tb-rdimm-ddr4-memory-support-in-upcoming-bios/

ASRock has tweeted out about how the well-known overclocker Nick Shih has used the ASRock X299 Taichi CLX motherboard to get an astounding amount of RAM installed. Nick Shih used the consumer-grade X299 motherboard (review here), which generally only offers support for up to 256 GB of non-ECC DDR4 RAM and loaded it up with 1 TB of RDIMM DDR4 memory.

The RAM that Nick Shih used were eight SK Hynix 128 GB LRDIMM (load-reduced DIMM) modules, even though the X299 Taichi CLX doesn't officially support ECC (or Error Correction Code) and doesn't offer any support for LRDIMM modules. LRDIMMs may look like typical DDR4 modules but they are currently only supported by workstation motherboards and no consumer X299 board can support it right now. However, that is about to change as ASRock is prepping up a new BIOS that would enable RDIMM support on the consumer-grade X299 motherboards with 7th, 9th and 10th Gen processors.