ZOTAC ZBOX CI660/ CI660 PLUS/ CI640 / CI640 PLUS/ CI620 /CI620 PLUS Tested memory BRAND Part no. Size Type HYPERX HX424S14IBK2/16 CTMH1611658 8GB DDR4-2400 SAMSUNG M471A1K43BB1 8GB DDR4-2133 APACER AS08GGB13CDYBGC 8GB DDR4-2133 SKHYNIX HMA451S6AFR8N 4GB DDR4-2133 SAMSUNG M471A5143SB0-CPB 4GB DDR4-2133 HYPERX HX424S14IBK2/8 CTMH08C1503 4GB DDR4-2400 KINGSTON KVR21S15S8/4 4GB DDR4-2133 SKHYNIX HMA82GS6MFR8N-TF 16GB DDR4-2133 SAMSUNG M471A2K43BB1 16GB DDR4-2133 KINGSTON KVR24S17D8/16-SP 16GB DDR4-2400