Full Details from Amazon.com : http://www.amazon.com/gp/product/B004AQIXHC?tag=onigi-20

4GB Upgrade for a Dell Precision Workstation T3500 System (DDR3 PC3-8500 ECC )

240-pin DIMM
DDR3-1066
DDR3 PC3-8500 Unbuffered ECC DDR3-1066 15V 512Meg x 72
The only brand of memory upgrade available directly from a DRAM manufacturer tested to meet the most stringent industry specifications
Install it yourself in about 15 minutes The same top-quality memory that the worlds largest computer manufacturers install in the systems they sell