Back in June, Facebook's veep of technical operations Jonathan Heiliger was lamenting that both AMD and IBM's latest chip designs aren't bringing his company the performance gains as advertised. We suspected the lack of results were more a result of a heavily customized Facebook stack that uses PHP and MySQL than hardware.

Terence Judkins, director of systems at Group One Trading, recalls a similar situation on his company's initial tests with Nehalem.

"When we first got Nehalem - the first server we got off the shelf - we did not get good results out of it. In fact, we saw gross degradation over the previous 5400 series," Judkins said.

After scrutinizing the drop in performance, he said his team realized they had hyperthreading on by default and had the power profile set for low power utilization.

"What happens in the market place is, the market will suddenly spike up, and there's no time for a core to get up to maximum performance. So by downclocking those CPUs, we saw a performance hit," Judkins said.

"When we set power performance to maximum and turned off hyperthreading, we saw a little over 200 per cent performance increase in our trading software. It was a world of difference by just a few settings. So maybe Facebook needs to do some of their own analysis on how they're deriving their business metrics."

For the whole article, visit http://www.theregister.co.uk/2009/10/07/intel_san_fran_nehalem_savings_chat/