Adding a GPU with external power to an HP Elite 8300 CMT

[WM1000]

I am planning on adding a GTX 750 to my HP Elite 8300 CMT. However, all the ones i seem to find have a six pin PCIexpress power, in which the power supply does not have. The power supply does not use a usual 24 pin connector, rather a proprietary connector. There are no SATA ports on the 320 watt power supply. Only the proprietary six pin connector for the psu, the four pin CPU connector, and another six pin connector of idk. However, there are these four pin thingies on the motherboard used for sata connection. No molex either. So could I use one of these sata to six pin PCIexpress adapters to power a GTX 750. The GTX 750 has a 55W TDP so overloading the power supply should not be a problem, as I used to have a GTX 750 in my system without a pciexpress conector. However that GTX 750 died. And I need a video card for the pc. The 8300 CMT is my main PC. So is it a problem if I use a SATA to 6 pin PCIexpress adapter (https://www.ebay.com/itm/15pin-SATA-Power-to-6pin-PCIe-PCI-e-PCI-Express-Adapter-Cable-for-Video-Car...) with a video card that has 55 watt TDP (GTX 750)?

Btw my CPU is an i5-3470.

With 8gb of ram, 128gb ssd and 1tb hdd.

[wb2001]

@WM1000,

What computer did you have where "as I used to have a GTX 750 in my system"?

See this link on the 8300 series. Make sure you also read the imbeded link.

[WM1000]

I used a GTX 750 in my 8300 CMT until the 750 died.