More companies are turning to x86 for larger, mission-critical workloads according to a new report from Forrester.

There's been a move away from RISC-based Unix servers as x86 servers have matured in such a way that have become viable options said the report, x86 Servers Hit The High Notes.

According to report author Richard Fichera, enterprises previously have had little choice but to use RISC Unix servers for high-end processing, even though they represented the expensive option. However, he said that the game changed when Intel brought out the Xeon 7500 and 6500 CPUs last year. "With this family of CPUs, Intel has fundamentally changed the dynamics of this segment of the server market. These processors now allow system vendors to build x86 servers that are realistic alternatives to the midrange of what has been an almost exclusive RISC/Unix franchise," he wrote

But there are other factors too. Fichera claimed that system vendors are improving the quality of their servers in other ways by improving memory access and using proprietary node controller chips to enhance performance. He also pointed out that x76 operating systems are improving too, with big leaps in stability and scalability.

However, the report goes on to show that, despite these improvements, there is still a considerable gap between RISC and x86 servers. Fichera claimed that the publicly available SAP two-tier SD benchmark demonstrates that x86 system performance is three to four years off the pace of the best RISC offerings. "The x86 platforms show improvements over the past 10 years that are proportionally higher than those of the RISC systems. It appears that, with a small margin of error, the high-water x86 result is about equal to the highest RISC result from three to four years previous." He also said that how big a gap there is between RISC and x*6 depends on the server manufacturer, in some cases, the RISC machine is only 50 percent better.

What's going to be interesting is seeing how future Intel processors will change this process. Earlier this week, Fichera blogged that "for servers, performance remains a work in progress, but third-party reviews of the performance of the first available product, the Core i7 2600K ... indicate significant performance gains on a per-core basis