So, I thought I put together a Windows XP machine based around an old P4 motherboard (Gigabyte GA-8IPE1000-L rev. 2 [1]) and some other old parts that I have lying around. I just want to play around with some software I used to use back in the day on hardware from that period.

One of the things I had on the shelf is this Semi-Modular Seasonic PSU [2] that I never used for anything but it's brand new so, why not...

Anyhow, this PSU has the extended ATX connector and the board takes the original. However, the connector on the PSU has the ability to bend away the extension but there is no room on the board for it to go, there is an IDE connector on one end and the memory modules are on the other. The connector is made in such a way that you can open/close the extension. I guess I can cut it so I bend the extension upwards. Should I?

Then the board itself has a 12v connector (near the CPU), do I need to connect that? The PSU has what looks like two 12v connectors coming out of it. The manual doesn't actually go into the details of this so I'm unsure but they seem to connect. Shall I connect one of them?

For video I have this Inno3D NVIDIA GeForce 7300 GT laying around. It takes a normal molex. I assume I connect that? I also have an ATI Radeon 9600 Pro that doesn't have a power connector. Should I pick one over the other?

[1] https://www.gigabyte.com/Motherboard/GA-8IPE1000-L-rev-2x#ov
[2] https://seasonic.com/core-gm