I ran SiSoftware's Sandra on my new PC, and for my CPU it reports:

Generation :        G8 / T29
Name :              TN0 (Trinity) FX/Opteron 32nm (ES)
Revision/Stepping : 0 : 10 / 1
Stepping Mask :     TN-A1
Microcode :         MU6F10010F

The (ES) is a well-known code in product development, meaning "Engineering Sample". Those are beta versions of the CPU, which still may contain some bugs, or even have features switches off. I contacted both the PC's manufacturer Medion as well as AMD about this.

I had to downvote the Medion helpdesk here. The person I talked to boldly said Sandra was wrong (without knowing how Sandra got this information; he didn't even know the software), and used the word "impossible". His conclusion was "We’re not taking this in consideration for service”. Right. So, if you like Medion for their good prices, but like good support even better, you may consider buying your PC elsewhere.

AMD was more helpful, but wanted to be sure before replacing the part (which I find reasonable). They suggested that I dismount the cooler from the CPU to check what was printed on it to be sure. I'm a bit reluctant here: I would have to wipe the thermal paste from the CPU, and won't know for sure my cooling will still be OK afterwards.

Questions

1. Has anybody actually found a confirmed ES CPU in her PC?
2. Is anybody aware of Sandra erroneously reporting CPUs as Engineering Samples?
3. How can you tell an ES, apart from the print on the package? Shouldn't Stepping Mask identify the CPU uniquely?