Amazon.com: Fasgear PCI-e 5.0 12VHPWR Extension Cable: 30cm/1ft 16Pin (12+4) Male to PCIE 2x8Pin (6+2) Female Sleeved Extender Cord with 4 Combs 16AWG GPU Cable Compatible for GeForce RTX 4090,4080,4070 ti Black : Electronics
ATX 3.0 PCIe 5.0 600W Dual 8 Pin to 12VHPWR 16 Pin Power Cable - MODDIY
It seems some 4090 owners are unaware PSU manafacturers have 12VHPWR connectors available. Here is a list of solutions for you to avoid using the including adapter which is causing problems. PSA :
ModDIY ATX 3.0 PCIe 5.0 600W Triple 8 Pin to 12VHPWR 16 Pin Adapter Cable MDY-T8PM-12VHPWR
Amazon.com: JOYJOM PCI-e 5.0 12VHPWR 16Pin Right Angle Adapter Female to Male Extension Cable, 16AWG 600W 12VHPWR 90 Degree Adapter for Graphic Card GPU 12+4pin RTX 3090Ti 4070Ti 4080 4090 (Type A) : Electronics
CORSAIR 2' Premium Individually Sleeved 12+4pin PCIe Gen 5 Type-4 600W 12VHPWR Cable Black CP-8920331 - Best Buy