We reported over the weekend on the 16-core processor from AMD, but if you want to get in early, you can buy the Opteron variant of it... right now. The AMD Operton 6300-series, or "Warsaw" processor, is designed for 2- and 4-way goodness in servers.
It uses the socket G34, and are based on the Piledriver architecture. The new chips feature between 12 and 16 cores, 16MB of L3 cache, quad-channel DDR3 memory and much more. They should have a much better performance-per-watt ratio over today's Opteron 6300 series, too. The company were poised to release these new CPUs later in Q1 2014, but ShopBLT is offering a pre-order on the 12-core version for $421, and the 16-core Operton for $663.
The details on the processors are as follows: the 12-core version is the Opteron 6338 HE, which has a 99W TDP. The 16-core processor, is the Opteron 6370 HE, and also has a 99W TDP. The HE stands for high efficiency, and should feature moderate clock speeds to keep the power numbers down.