https://www.ebay.com/sch/i.html?_nkw=Addon+8Gb+Factory+Original+Rdimm+For+Hp+731761+B21+Ddr3+8+Gb+Dimm+240+Pin&_sacat=0&_dmd=2

Addon 8Gb Factory Original Rdimm For Hp 731761-B21 - Ddr3 - 8 Gb - Dimm 240-Pin

$150.00
$97.00

DDR3 - 8 GB - DIMM 240-pin - 1866 MHz / PC3-14900 - CL13 - 1.5 V - registered - ECC