There are at times a significant difference between synthetic benchmarks that are run on CPUs and other hardware and the real world performance that parts are capable of delivering. The problem is that the software and environments that servers and processors run on in the real world are often vastly different that the industry standard server benchmarks.

An example is criticism from Facebook Vice President Jonathan Heiliger who claims that the new servers the social networking site uses are not showing the performance gains that Intel and AMD touted in the press.

According to Heiliger, engineers at the company are not seeing the performance gains expected. AMD has responded to the criticism from Facebook and eWeek reports AMD said that its CPUs are among the highest performing and most efficient available. AMD agrees with the issues on benchmark discrepancies with real world performance and says that what is needed most are benchmarks that reflect real world usage more accurately.

Heiliger said at the Structure conference on June 25, "The biggest thing that surprised us … is the less-than-anticipated performance gains from new microarchitectures. The performance gains they are touting in the press, we are not seeing in our applications."

AMD's Nigel Dessau defended the performance of AMDs Opteron processors saying that the problem for Facebook is that the company runs a highly specialized software stack and performance may be off because its applications run more PHP and Java than C++.

Dessau wrote, "Let's face it: Synthetic benchmarks are essentially a useful evil. Everyone wants to know how a certain technology performs against a standardized test, but what happens when that test [bears] no real resemblance to the real work people do? You get a huge disconnect."

AMD says that its new six-core Opteron parts are striking a balance between performance and energy efficiency. Energy efficiency has become as important to enterprise users as raw performance over the past several months.