So its been almost 10 years since i've swapped computer parts and I am nervous about this. Ive never done any homelab type thing involving big powerful parts, just dealt with average mid range consumer class parts in standard desktop cases.

I do computational work now and want to convert a desktop pc into a headless server with a beefy GPU. I bit the bullet and ordered a used P100 tesla 16gb. Based on what im reading, a new PSU may be in order as well if nothing else. I havent actually read labels yet but online info on the desktop model indicates its probably around a 450~ watt PSU.

The P100 power draw is rated at 250 W maximum. The card im using now draws 185 W maximum. Im reading that 600W would be better for just-in-case overhead. I plan to get this 700W which I hope is enough overhead to cover an extra GPU if I want to take advantage of nvidia CUDA with the 1070ti in my other desktop.

How much does the rest of the system use on average with a ryzen 5 2600 six core in a m4 motherboard and like 16gb ddr4 ram?

When I read up on powering the P100 though I stumbled across this reddit post of someone confused how to get it to connect to a regular consumer corsehair PSU. Apparently the p100 uses a CPU power cable instead of a PCIE one? But you cant use the regular cpu power output from the PSU. Acording to the post, people buy adapter cables with two input gpu cables to one output cpu cable for these cards.

Can you please help me with a sanity check and to understand what i've gotten myself into? I don't exactly understand what im supposed to do with those adapter cables. Do modern PSUs come with multiple GPU power outputs/outlets from the interface these days and I need to run two parallel lines into that adapter?

Thank you all for your help on the last post im deeply grateful for all the input ive gotten here. Ill do my best not to spam post with my tech concerns but this one has me really worried.