A-Tech Components 8GB Kit (2x4GB) Memory Ram for the Acer Altos G540 R520 R720 R920 PC2-5300 DDR2 ECC FB DIMM Fully Buffered Server Memory 8GB Kit (2x4GB) PC2-5300 DDR2 ECC Fully Buffered Server Memory Genuine A-Tech Memory Designed for the Acer Altos G540 R520 R720 R920 Toll Free Technical Support at 1-866-557-4527 Lifetime Warranty