Allan, I beg your pardon but, IMVHO, you're doing it wrong..
if you need a reliable server, you'd have to choose a certified hw, i.e. choose something coming from HP, IBM, Fujitsu and so on.. all these brands have RH certified hw and SME will install on them without any issue..
for HP, you can check here:
http://h17007.www1.hpe.com/us/en/enterprise/servers/supportmatrix/redhat_linux.aspxyou may say that a branded hw would be more expensive and from a bare economical point of view you're right, but choosing such a products you'll never have any issue.. moreover, you may have a warranty and a after maket support..
I have used dozens of HP' server and never had a single issue since (at least) 10 years..
back to your issue:
check (as zatnikatel) if your MB uses UEFI and if your graphic card has some parameters to work in VGA mode (such an adapter is useless in a headless server)
check if your MB is supported by RHEL6/CentOS6.X
check if your graphic card is supported by the same OSes
don't use onboard raid (if present) because, at 99.99%, is a fake one