Today I checked my 2 Windows 8 Pro keys I got from dreamspark with Online PIDChecker. I noticed that the info of both keys was almost identical. They are for the same edition so of course most info should match. But I was very surprised to see that the Activation ID was exactly the same for both keys! It gets even better: there's very little difference in the productId. Windows 8 Pro x64 vs x86: first part is the same, second part +2, third part -38882, last part + 90. Windows 7 Pro x64 vs x86: first part is hidden, second part is same, next part is -9115, last part -116 You see, they are quiet similar, but not that WOOOW. Most interesting are these however. For this products I have 2 keys of the same architecture: Windows Vista Business x64 (both keys x64): first part is hidden, second part is same, next is +25, last is -30 Windows Vista Business x86 (both keys x64): First to second key: first part is hidden, second part is same, next is +25, last is +597 For both producs the 2nd last part is + 25... Other keys have the same type of similarities. Probably I'm just freaking out, but I found this pretty interesting. I'm not looking to crack anything or generate our own keys or whatever, just out of interest. EDIT: The PIDChecker also does something wrong. On my Windows 8 Enterprise with default key (unactivated) the pid in registry differs in the last 3 digits from the one that the PIDChecker creates with the same key. So the PIDChecker didn't calculate the PID correctly.