Is there something I'm missing, like AM3+ just being an AM3 socket with a chipset update? Well, if it is like the AM2/AM2+ transition, a few of the AM2 boards could be flashed to accept AM3 CPUs, but ...
We've had high core counts, decent single-core performance, and thermally efficient CPUs for years now. Comparing an 8-year-old CPU to a modern chip will show you a huge performance gap, but ...