Really not trying to be a doomsayer here, but you guys do realize the CPU in this computer is worse than a Core 2 (and older), and throwing a GTX 960 or similar in there is just utter overkill (it will be so horribly bottlenecked), to say nothing of PSU compatibility. The GeForce 6150 is older than Oblivion, if that helps put things in perspective, and it probably only supports PCIe 1.0 (its an nForce 4 derivative and afaik it wasn't until nForce 600 or 700 that 2.0 was supported); that may cause compatibility issues with newer cards (in principle/theory it shouldn't, and I wouldn't believe that it could if I hadn't seen it happen with my own two eyes and then gone and looked into it a bit more, and indeed there are rare cases of older motherboards not playing nice with newer cards). If I'm reading the HP specs right as well, this machine is maxed at 4GB of RAM.
Upside, the HP website indicates the motherboard should automatically disable the 6150 if a standalone graphics card is installed, so as long as the PSU thing isn't a problem (e.g. you upgrade) it should be okay. My honest, no-joke advice here? Get something cheap off ebay like GeForce 8600 or similar - it'll be low power, it'll be cheap, and it'll be a nice improvement over the 6150 (as in, it'll at least *run* games like Oblivion, FO3, FONV, Skyrim, etc). Save up your pennies and get a newer/faster computer down the line (doesn't have to be brand new - there's tons of used/refurb/etc machines out there that would be an overall upgrade) - if you're after ENB and tons of graphics mods (I'm assuming in Skyrim or FO4) this machine is probably never going to get you there, because even if you go out and drop a lot of money on a flashy new graphics card and big PSU to run it, the CPU and everything else are pretty dated and (unfortunately) kind of a dead-end for upgrades (and it really isn't worth the money to go track down a Phenom II and "max out" this HP).
Now, that said, there's nothing wrong with this HP as a machine I'd assume (e.g. it sounds like it still works), so once you've upgraded, it would make a nice HTPC or backup system or whatever.
Purr4me beat me to it. The power supply will be a required upgrade for any useful add-on upgrade. I'm fairly sure that the 6150se won't even run Fallout 4 at all even if you got non generic drivers to install. I've had problems trying to do it with Intel integrated graphics from newer i5's and i7's and they're quite an upgrade from the 6150se.
The 960 is a solid choice and I would suggest a 450watt power supply to go with it.
No way that 6150 can do FO4 - it requires DX11. The CPU and memory here will never be upgradeable to hit FO4's system requirements though, since they're spec'ing 8GB of RAM and a newer/faster CPU along with a relatively powerful DX11 card. nVidia has the system requirements listed out on their GeForce Experience page here:
That Phenom II X4 is like the absolute maxed out top-end floored upgrade option for this HP, but you're still stuck with 4GB of RAM and those Phenom chips are not cost effective (not to mention all the other "stuff" that would likely have to go along with it, before you're even talking about a new graphics card, and you're still stuck on that 4GB of RAM).
Edited by obobski, 03 April 2016 - 12:13 PM.