Is it safe to use a pigtail cable for 2x8-pin to 12VHPWR adapter on an old cheap PSU?

Posted by selar4233@reddit | buildapc | View on Reddit | 3 comments

My current specs:

I'm planning to upgrade to an RTX 5070, specifically Palit Infinity 3, which comes with a 2x8-pin to 12VHPWR adapter. My PSU can supply up to 600W on 12V rail, but there are some implications. It is an old ATX 2.4 PSU, and it is ranked as E-tier in SPL's PSU Tier List. Moreover, even though it has two 8-pin connectors, they are pigtailed from a single PCIe cable, and this raises some concerns about safety of the GPU/PSU. RTX 5070 has a 250W TDP, and with PCIe slot supplying 75W it leaves only 175W of load on the cable, so it might be fine?

So, has anyone tried using 12VHPWR adapter with a pigtail cable from an old cheap PSU? I can pick up a Cougar GR850 with a native connector, but I'd like to avoid spending money on a new PSU.