OEM PC Compatibility

[AydenTPC]

So I am doing a new build project where I am taking an OLD OEM machine and trying to turn into a light gaming machine using strictly used components. My OEM PC is an old 2011 HP Pavilion (p7-1200 series) with a i5 2400, 8GB RAM, and 1TB HDD. I've already bought a pretty good PSU for cheap but am looking for a GPU. My only concern is the compatibility, especially considering this is a HP machine. I've heard in especially older HP machines that the firmware prevents from a 3rd-party card working with the system, but others have said to try to get a card that's the same age of the MOBO and it will work. So I'm thinking about getting a 600-series NVIDIA GPU but do I actually have to go for matching age components. Is there some kind of BIOS or firmware issue that prevents more modern cards from working with older boards?

[it_dont_work]

Some have issues booting with older bios (pre uefi) hp's seem to be the most common with that issue, but might be worth giving it a shot, my htpc is a hp ssf about the same gen with a 2500 and a low profile 1050ti

[AydenTPC]

21 minutes ago, it_dont_work said:

Some have issues booting with older bios (pre uefi) hp's seem to be the most common with that issue, but might be worth giving it a shot, my htpc is a hp ssf about the same gen with a 2500 and a low profile 1050ti

Could you explain "pre-uefi"? I'm familiar with most PC terms but haven't had much experience in tinkering with BIOS and UEFI. I'm assuming you mean older boards didn't have a UEFI and that's why a newer more modern GPU isn't comaptible?

[it_dont_work]

1 hour ago, AydenTPC said:

I'm assuming you mean older boards didn't have a UEFI and that's why a newer more modern GPU isn't compatible?

yeah, that's what it means your board is from a period of change between the older systems and using uefi systems to communicate with hardware, I'm not sure but from memory the hp boards of about that era used intels version of efi which was pretty locked down for business use. 

[AydenTPC]

17 minutes ago, it_dont_work said:

yeah, that's what it means your board is from a period of change between the older systems and using uefi systems to communicate with hardware, I'm not sure but from memory the hp boards of about that era used intels version of efi which was pretty locked down for business use. 

So did those older HP boards use Legacy BIOS instead of UEFI? Wouldn't that mean a 600-Series NVIDIA GPU could work as they are compatible with a Legacy BIOS?