Power supply for a used SFF office PC - did I mess up?

Shmael1053 · August 22, 2018

I'm currently trying to build my first gaming PC on the cheap. The method I'm trying is to buy a used office PC with good base specs and to slap a mid- to high-tier graphics card into the thing to let it run games.

Specifically, I've purchased an HP EliteDesk 800 G1, small form factor edition (the one with a DVD drive in the upper left corner, not the ultra-slim model or full tower) with an i7-4770 inside. Immediately upon getting it home, though, I realized an issue: while the motherboard has an available PCIe x16 slot, the power supply is custom-made for the system and doesn't have any extra cables.

Worse yet, it's only 240 watts. While the TDP of the processor and most small form factor GPU's would still be below 240, almost every graphics card I've seen recommends a minimum 400 watt PSU.

I've done a little research and have seen some threads claiming that upgrading the PSU in a prebuilt small form factor PC is either impossible, or not worth the hassle of rewiring all the custom power connections on the (usually custom) motherboard. I'm starting to worry that I wasted my money and should have gone with a full tower.

Is it possible for me to (safely) jury-rig a 6-pin PCIe power connector onto the existing power supply?

If not, is it even possible for me to upgrade the PSU of a SFF prebuilt with a custom motherboard?

Stefan Payne · August 22, 2018

7 hours ago, Shmael1053 said:

The method I'm trying is to buy a used office PC with good base specs and to slap a mid- to high-tier graphics card into the thing to let it run games.

Won't work because of the proprietary PSU used in many of those models.

Often times you see +12V Only PSU and Drives getting power from the Motherboard.

So the best you can do is putting a Graphicscard without a 6 or 8pin power connector on the Board.

Using adaptors might burn the Motherboard...

Shmael1053 · August 22, 2018

7 hours ago, Stefan Payne said:

So the best you can do is putting a Graphicscard without a 6 or 8pin power connector on the Board.

Yeah, I saw Craft Computing's $220 gaming PC video and got carried away. He forgot to mention the custom PSU/motherboard issue.

It's actually worse than I let on, I majorly jumped the gun and won an eBay auction for a ZOTAC 1060 mini assuming I'd be able to figure out the power supply by the time it showed up. Thankfully the seller was awesome and let me cancel the order that night. Currently shopping around for a 1050Ti instead.