I pulled another 1.83 T5600 Core2Duo, and I have two more to pull. The 2.13 is actually slightly chipped on the corner and I do not know if it'll affect how it'll work. If you want, I'll gladly send you a few 1.83ghz Core2Duos for just the cost of shipping. I guess I can send the 2.16 and two 1.83ghz T5600 chips and if it works for you than great and then you'll have spares for any other machines you may get. I am never going to actually bother putting this 2.13 in anything for myself and the machines I fix for family/friends I am not going to bother upgrading them for a few more megahertz.