I am also getting the PSOD running on ESXi 5.1 using HP BL490 G6 and BL490 G7 blades. According to this link https://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/topIssuesDisplay/?javax.portlet...
It does not address the server models I am using. Attached is a screenshot of the PSOD.
***Update ***
It does appear that BL490 G6 and BL 490 G7 are also prone to this issue.