MP 1,1-5,1 Obscure HIS 280X in a 2009 Mac Pro

[dcbl]

I happen to have on hand a HIS 280X that's been in my old PC and I'd like to try putting it into my 2009 Mac Pro to upgrade beyond High Sierra. HIS seems not to be a popular brand and I have it because it's what I could get my hands on in a hurry 8 years ago, but there's very little info about the card online. For reference, here's a couple links with specs:

HIS Product Page
Newegg Product Page

It's a fairly thirsty thing with a TDP of 250W. Could the Mac Pro's PSU supply enough power? What kind of power cables might I need for it? And if the power consumption is too high would I be able to undervolt it to bring it within an acceptable range?

Aside from power concerns, are there any resources that might work to flash this card given how obscure it seems to be?

Thanks!

 

[dcbl]

After a lot more reading and watching I think there's no way to give this card enough power with what's already available on board so I've ordered the parts to do the Pixlas mod.

Does anyone have any advice for me or could point me in the right direction about potentially flashing this card to get boot screen support or is that a lost cause?