No you heard incorrect rumor of 24 to 8 pin.  This adapter you saw is incorrect. you have two options: Dell sells oem psu of 360w that has same form factor as your stock psu.  It will fit like a glove.  It has one black PCIe connector for graphics card that can use it.   H360EGM-00 19YR3 Power Supply,360W,Environmental Protection Agency,Gold,Medium Tower,Chicony Corp.   [IMAGE]   Or you can get a 24 to 6 pin adapter from Amazon then a SFX psu that is small enough, if you have 3070 tower (35.05 x 27.43 x 15.49 cm).  for example, silverstone 750 w SFX dimensions 125 mm (W) x 63.5 mm (H) x 100 mm (D).  cooler master sfx 750 (125mm x 100mm x 63.5mm). If you have 3070 SFF, then this option is not great because SFF case (29.21 x 28.96 x 9.4 cm) is too small to fit a SFX psu.  [IMAGE]  
I have a dell Optiplex 3070, it has a GT710 and I was thinking of upgrading my graphics card. To do that, I also need to upgrade my PSU. The power supply that Dell has pre-installed is a 260W power supply, which isn't enough to run the graphics card. I've done research and everyone says you can easily change the power supply if you use a 24-pin to 8-pin adaptor, however my motherboard only has 6 pins, and all the 24-6pin adaptors, everyone complains about a error 515, and it also has 1 extra white wire which I can't seem to understand where to plug in. Would greatly appreciate if anyone would help with this! Thanks![IMAGE]
Dell Optiplex 3070 PSU Upgrade