Liquid-cooling memory modules with liquid flow pipes between memory module sockets

A liquid-cooled computer memory system includes first and second blocks in fluid communication with a chilled liquid source. A plurality of spaced-apart heat transfer pipes extend along a system board between memory module sockets from the first manifold block to the second manifold block. The heat transfer pipes may be liquid flow pipes circulating the chilled liquid between the memory module sockets. Alternatively, the heat transfer pipes may be closed heat pipes that conduct heat from the memory modules to the liquid-cooled blocks. A separate heat spreader is provided to thermally bridge each memory module to the adjacent heat transfer pipes.