Can I go network card to network card (no switch) with 40g? I have 10g nics in my computers now and during large file copies I'm maxing out the 10g (no switch). I'm currently doing 10g over cat6a and it is maxed.

[JMill9]

I was considering getting 2 of the XL710-QDA2 cards and a XLDACBL3 QSFP+ to QSFP+ Twinax Cable |

[VincentT_Intel]

Hi JMill9, Thank you for posting in Intel® Ethernet Community. Back-to-Back connection between 2 XL710-QDA2 is supported. Please refer to the "Notes" section of the link below for additional information regarding the setup. https://www.intel.com/content/www/us/en/support/articles/000006051/network-and-i-o/ethernet-products.html Hope this helps. Best Regards, Vince T. Intel Customer Support Under Contract to Intel Corporation

[JMill9]

Thanks. Best regards, Jim Millerick Complete Systems Design http://www.csdits.com<http://www.csdits.com/> 310.621.9567

[JMill9]

Sorry – one more question – is there a noticeable difference between the performance of DAC and fiber? I hear CAT6 has more collisions or overhead or latency on 10gigabit (not sure what is true) than fiber. Best regards, Jim Millerick Complete Systems Design http://www.csdits.com<http://www.csdits.com/> 310.621.9567

[VincentT_Intel]

Hi Jim, With your intended setup of back-to-back connection within 3 meters, there should be no difference between using DAC and fiber. Also, the XLDACBL3 cable features low cross-talk and pair-to-pair skew that maintains signal integrity. For more information about the features of Intel QSFP+ cables, kindly visit the link below. https://www.intel.com/content/www/us/en/ethernet-products/optics-cables/ethernet-qsfp-cables-brief.html Please let us know if there's other assistance needed. Best Regards, Vince T. Intel Customer Support Under Contract to Intel Corporation

[JMill9]

Thank you very much! Best regards, Jim Millerick Complete Systems Design http://www.csdits.com<http://www.csdits.com/> 310.621.9567