For dual-CPU Mac Pro 4,1 2009 upgrade. Note that different from many sellers, this product has CPU die like a mirror. No residues of solder, thus much better thermal conduction.
You may need some other items to install your CPU. 4,1->5,1 firmware update program. You can download from github. 90% alcohol chem pad and thermal paste.
You can see how our. Looks like in above video. Mac Pro 2009 4,1 (to 5,1) Delidded CPU Install Guide (x5680 x5690 12-core CPU Upgrade). Video will open in a new window.
For testing we used pencil eraser and then used 90% alcohol to clean the pin contacts before install. Just in case it cannot boot for you, the first thing I'd try is to clean them again. Any questions about installing it are very welcome. This item is in the category "Computers/Tablets & Networking\Computer Components & Parts\CPUs/Processors". The seller is "dqupgrade" and is located in this country: US.This item can be shipped worldwide.