The new PICMG COM-HPC Specification provides system and interface flexibility by adopting a pair of 400 pin connectors to link Modules to Carrriers.  Samtec COM-HPC^®-aligned connectors support existing and future interfaces such as PCIe^® 5.0 (32 GT/s) and up to 100 Gb Ethernet.
The male carrier plugs vary to allow for either a 5 mm or 10 mm stack height.  For 5 mm stack height, the module receptacle is ASP-209946-01 and the carrier plug is ASP-214802-01.  For 10 mm stack height, the module receptacle is ASP-209946-01 and the carrier plug is ASP-209948-01.
COM-HPC Connectors feature an open-pin-field array, which maximizes grounding and routing flexibility by allowing system architects to route high-performance differential-pairs, single-ended referential signals, and power, via the same interconnect. 

With a small 0.635 mm pitch, the COM-HPC connectors feature an ultra-micro footprint compared to COM-Express solutions.
COM-HPC connectors use a 2.2 / 2.4 / 2.2 mm row pitch.  The spacing allows PCB designers more room to route differential signals.  Crosstalk is improved with the increased space and the ability to add more ground vias around the differential signals.