Figure 1. Supported configurations for PowerEdge C6420
Chassis configuration summary table
Table 1. Chassis configuration summary table 
PE C6400 Chassis Config. PEC6420 support PEC6525 support
24 x 2.5" SAS/SATA Backplane Yes Yes
8 x 2.5" NVME + 16 X 2.5" SAS/SATA
backplane
Yes Yes
12 x 3.5" SAS/SATA Backplane Yes Yes
Diskless No backplane Yes Yes
Expander Backplane Yes No
24 x 2.5" All/PURE NVME backplane No Yes
Dell EMC PowerEdge C6420 overview 7