2GB [1x2GB] RAM Memory Upgrade for Dell OptiPlex 745 Systems (DDR2-800, PC2-6400) Guaranteed Compatible for the Dell OptiPlex 745 Desktop Towers Speed up your system with up to 8.0GB of Memory! Lifetime Replacement Warranty! Will ship the same day when ordered at or before 4pm EST! All others ship next day! Fully-staffed call center to help with installation or inquiries! Call 866-335-1355 with questions or for help!