Hynix 8GB Kit (2 x 4GB) PC2-5300F DDR2 ECC Fully Buffered Server Memory. A matched pair of Hynix 4GB FB-DIMM modules for servers and workstations. Specs: 4GB per module (8GB total), DDR2-667 (PC2-5300F), 2Rx4 dual rank, ECC Fully Buffered, CL5, 240-pin, 1.8V, full part code PC2-5300F-555-11.

Important — this is FB-DIMM (Fully Buffered) server memory. It is NOT compatible with standard desktop or laptop computers—it only works in servers and workstations that specifically take PC2-5300F fully buffered memory. Commonly used in the Apple Mac Pro (2006–2008, models 1,1 / 2,1 / 3,1) and various Dell PowerEdge and HP ProLiant servers of that era (e.g., Dell 1950/2950, HP DL360/DL380 G5). Buyers should confirm their specific system uses PC2-5300F FB-DIMM before purchasing.

Sold as a tested, working pair. A great way to upgrade a classic Mac Pro or keep an older server running. Note: for Mac Pro use, Apple's oversized heatsinks/heatspreaders are not required for the system to function.