[jing]

DAC is an order of magnitude cheaper than optical and might be fine for their use based on their comments of cat6 v cat6a and "short runs in their lab".

Also, if they are using two or three NICs per box, you'd need to factor in the cost of two / three of the X540's vs. a single 40gbe connection and you'd need to double the cost-per-port of the switch vs the 40gbe option.

[kev009]

Also intel NICs aren't a very good deal, and the driver quality isn't what it once was in common *nixes. The stateless 2x10g and 2x40g cards from Chelsio are cheaper and all around better IMHO.

[virtuallynathan]

Yep, that is also a very good point!