Maximum PC

There's no guarantee that any core's can be unlocked on fused CPU's...it's really just a lottery on what you get. Some boards have found their way around these fusings, but then again some of these CPU SKU's just can't do it with these board maker's tricks employed. I could go deep here, but I just oddly refrained!

Luck of the draw dude. Dance with the one you brought or pay to play again. AMD's binning process is so wide-ranged, I wouldn't try another unit. You bought an X2 and that board with hope for more (I assume), it didn't work, and there's not much more to do there man. However, you've tried to unlock the "other two cores". Is there anything out there talking about unlocking "one of the other cores" perhaps? Hmmm? I feel the x4 on the cheap is deep-sixed, but an x3 may not be off the table at this point.

(You may have a CPU destined to be an x4 but failed hard. But instead of the trashcan it went through the x3 validations. It didn't fully pass the tests but did as an x2. A weak 3rd core doesn't make it "bad" in most user's eyes and is worth looking into unlocking)

That's kinda what I figured. Thank you. Maybe I'll pose this directly to AMD. Or perhaps I should just hold out for a hex core around tax time lol.

Thanks for the input, much obliged!

No reason to take it to AMD. They'd likely give you a more obscure reply than Chum just did. The Callisto cores never boasted a great yield. Since cheaper dual cores are generally in greater demand than pricier quads, Global Foundries was directed by AMD to lock quads so that they could backfill orders for X2's. It still happens periodically during the production process, and as a result some lucky buyers get fully functional quads for half price. In other cases, buyers receive defective quads with the offending cores deactivated. It really is the luck of the draw.

There should be options in your BIOS to unlock, overclock, and over-volt, each core individually so there is a possibility of running it as a tri-core. The most likely scenario is that you received a defective quad core, or a legitimate dual core CPU. Let's not forget that GF does actually fab dual core Callisto. In either case, your best course of action would be overclocking the CPU as is. A decent aftermarket cooler, and a modest overclock of an X2 555 is not bad. Depending on how you use your rig, it may be all you need.