As the other answers have covered, this has already been available for over a decade.
The Core i7-920 was launched in Q4 2008 and supported tri-channel memory. https://ark.intel.com/content/www/us/en/ark/products/37148/intel-core-i7-940-processor-8m-cache-2-93-ghz-4-80-gt-s-intel-qpi.html
What the other answers do not cover is that 99% of people will not notice a difference. The biggest advantage for the average user is that dual-channel (or better) memory configurations help noticeably in gaming performance when using an:
- integrated GPU - https://www.youtube.com/watch?v=s_2Z208nDGE
- dedicated GPU - https://www.youtube.com/watch?v=-k5wA7EFwpo
If you look up specs for LGA 775 motherboards then you will find dual-channel support going back even further such as https://www.newegg.com/Product/Product.aspx?Item=9SIA4RE8205361