I would say a 750 ti, 950, 760 maybe? You could get a cx450m for 20 bucks after rebate
This is a SFF PC, won't fit an ATX PSU. These machines use proprietary PSUs, so you're stuck with those 240W, and often a 25W limit on the PCIe slot.
28 minutes ago, LukeIsLoveLukeIsLife said:
I've recently watched the "Upgrading the $69 dollar gaming PC" video and wanted to try it on my HP Compaq system as well. I currently have an R7 240 in it (yes, I've "modified" the case to fit it in) and I don't have to worry about the power limit since it's just around 20-25 max TDP. Now, I want to upgrade it, so I'm looking for the perfect GPU to fit it in there without comprimising safety. The prices are kind of near each other, and so I don't have a problem with that. I would like the GTX750/750ti since it gives the best performance out of the three. The RX550 is just slightly lower than the GT1030, but also cheaper at around $8-$10.
TL;DR Which graphics card should I put on a system with a 240W max power supply.
The GT1030 (GDDR5 mind you, not the DDR4 version because it's utter crap) is a safe buy, as it almost always works. The most powerful option is the GTX750Ti, but you'll have to see if it will actually power up.