Tilera has announced that they have created the world's first 100-core chip — the 100-core TILE-Gx100. This chip claims to have four times the performance of any chip announced to date. They claim to have ten times better computing efficiency than Intel's next generation Westmere processor.
So what's the downside?
Tilera is a relatively new company that was started around 2004. While that could be a negative, they seem to have funding to keep them going. More on the downside is that the architecture of the chips is different. It doesn't use the x86 architecture that Intel and AMD use.