Speaking about an HP 5400 zl Switch series and the 8-port 10GBase-T v2 zl Module (J9546A)...I'm not totally sure (because references exist about J9538A which is an 8-port SFP+ v2 zl Module and not directly about J9546A) but if the same considerations valid about a J9538A can be ported to J9546A there is a particular requirement to deploy optimized 10G ports connectivity: ports A1 - A8 are grouped into two (and once connected they share each) Channels each one with 23.4 Gbps bandwidth (Group 1: ports A1, A4, A6 and A8, Group 2: ports A2, A3, A5 and A7)...for an total aggregated module bandwidth of 23.4+23.4=46.8 Gbps (thus 8x10 Gbps means you can have a oversubscription scenario if all 8 ports are concurrently connected or if just some are in a particular configuration, as reported above)...so the advice is that to guarantee wire rate connectivity you should pay attention to not connect more than one 10G port to a Channel (!).
In other terms...you should, as example, connect Server 1 10G NIC port to A1 and Server 2 10G NIC port to A2 (or any port of Group 1 to Server 1 and any other port of Group 2 to Server 2).