Of course! If you want to upgrade the CPU in your older 2013 Mac Pro and reapply thermal paste, grab yourself a new CPU like the E5 2667 v2, get some precision tool kits, antistatic protection, alcohol wipes, some thermal paste (preferably Arctic MX6), and a silicon mat or a way to keep your screws tidy. Begin by binding the break down the machine, take out the RAM and after that commence work on the fan and heat sink followed by the logic board. Remove the old thermal paste from the GPUs and CPU using alcohol wipes, S -reapply fresh thermal paste and put the components back in. Always be sure to use static precautionary measures so as not to hurt the parts. And once all has been put back together, check the Mac Pro to make sure it runs and starts properly.