Cpu 4 pin is industry standard and not proprietary. You can use an Amazon 24 to 6 pin adapter to connect the 24 pin psu to motherboard.   adapter COMeap 24 Pin to 6 Pin ATX PSU Power Adapter Cable for Dell Motherboard with 6 Pin Port 13.3-inch(34cm) on amazon [URL] If I were you I would instead get a Dell oem 360w psu that fits the case like a glove, has a 6 pin PCIe adapter for gpu, and return the bulky 24 pin psu, but that is up to you.  The 6 pin PCIe is effectively 8 pin (has 3x12V) can be adapted to 8 pin using a straight adapter.  Dell 360W Power Supply L360EGM-00 K38XP [URL]
Hello everybody, I've got an inspiron 3881 with an intel core i5 10400 and a 260W psu. As the 1660 super requires a 8 pin pcie, I've bought a Corsair CV550 PSU. Does anyone know how I would go about upgrading the psu and gpu, as the motherboard has a proprietary 6 pin power requirement, and the psu has a 24 pin. Also, I'm wondering if the CPU 4 pin is proprietary too or not. I will be operating the psu from the outside of the case, any safety advice would be appreciated. Thanks!
Inspiron 3881 PSU upgrade and ZOTAC GAMING GeForce GTX 1660