Please check out this awesome review of the Dell S6000-ON Top of Rack SDN Switch courtesy of IT Pro. (http://www.itpro.co.uk/) SDN ready, open networking platform, and yes, fast as hell.
Performance is all in the specs. It can be setup with 32 40GBe QSFP+ ports or 96 (yes you heard correctly) 10GbE SFP+ ports with (8) 40GbE ports still available. All in a 1U rack space. Basically, it glows red.
http://www.itpro.co.uk/switches/25369/dell-networking-s6000-on-review
Please contact us if you would like to see one of these switches in action!