It is true that x86 is the large majority of servers. However, until recently, the largest x86 servers had 8-sockets delivered by HP, Oracle, etc. Just recently, large 16-socket or even 32-socket x86 servers has just arrived (HP Kraken which is a redesigned Unix Superdome, and SGI UV300H). The large SGI UV3000 servers are clusters with 10.000s of cores, capable of only running HPC number crunching workloads. If you want to run business workloads, such as SAP, large databases, etc – you need a large scale up server. And these business servers maxes out at 16- or even 32-sockets. If you look at the SAP benchmarks, the largest servers are 32-sockets. There are no 10.000 core clusters such as SGI there. Clusters can not run business workloads.

So, for large business workloads, such as SAP, databases, etc – you must go to a large scale-up server with 16 or 32 sockets. And that market belongs exclusively to Mainframes and Unix RISC servers. Just recently 16-socket business servers x86 have arrived but I have not seen any benchmarks yet. Probably the performance is quite bad as they are the first generation. It takes a couple of decades before you get good scalability. RISC and Mainframes have done scaling to 16 and 32 sockets for decades. I expect the first ten years, x86 servers will lag behind seriously in performance and RAS. And if we look at the offifcial SPARC M7 cpu benchmarks, it is typically 2-3x faster than the fastest x86 cpu and POWER8 cpu. This Fujitsu SPARC M12 is almost as fast as the SPARC M7 cpu in general. This means that large 16 or 32-socket x86 servers will have a hard time catching up in the Enterprise busines arena – which belongs to RISC and Mainframes. First, x86 scales bad. Second, x86 is way slower than RISC. So I doubt x86 will threaten RISC and Mainframes in the large business server arena. There are no fast SAP benchamrks, neither fast TPC database benchmarks.