All PowerEdge 6850 servers support PC2-3200 (400MHz) DDR2 fully-buffered, ECC-registered memory DIMMS when installed in matching pairs. Memory is installed in riser boards and up to four (4) riser boards may be installed into the PowerEdge 6850 for a maximum of 64GB.
Dell part numbers for memory normally signify individual DIMMs, whereas third-party memory like Kingston sometimes come in kits of two DIMMS. Check a product's description for details.
All prices are in USD.