CT756128 - Crucial 4GB DDR2-667MHz PC2-5300 ECC Fully Buffered CL5 240-Pin DIMM Memory Module for Precision Workstation T5400

Energy-Efficient FBDIMMFor Energy-Efficient memory, please be certain that your system supports 1.5v Energy Efficient memory prior to ordering. For more information please visit the Energy Efficient Memory homepage.FBDIMM for Apple Mac ProNote: Because Crucial carries modules with more than one design of Apple-approved heat spreaders, your module may look slightly different from the example shown above.Because it's designed to deliver improved performance for demanding applications, FBDIMM memory tends to run at a higher temperature when compared with other DRAM. And that stands to reason as the MacPro ' running at speeds up to 3GHz ' is the fastest Mac system to date.