Fjjm, My first thought would be that the Broadcom driver is causing the issue. I found this regarding the PSOD - [URL] When you updated to 5.5, where did you get the ISO from? Dell or Vmware? You can update that driver with the download located here - [URL] Let me know how it goes. 
I have two R710 that was working fine with VmWare 5.0. Since I have reformat them with VmWare 5.5 they crash on reboot. The issue is exactly the same on the two servers. If I powered down and then powered up them the boot succeed. When the reboot failed, I have a message on the LCD screen E171F PCIe fatal error on Bus 0 Device 1 Function 0 . Review & clear SEL and a VmWare PSOD [IMAGE] I exclude an hardware issue because the same issue occurs on two servers and occurs just after the setup of VMware 5.5. May be something in the BIOS or a VMware bug. Any clue ? Thanks System Model PowerEdge R710System Revision IIOperating System VMware ESXi 5.5.0 build-1331820BIOS Version 2.1.9Firmware Version 1.50 (Build 24)
R710/VmWare 5.5 crash on reboot