Solved Having trouble finding a compatible PCIe Power Connector for dual GPU build

My new PC build has been freezing frequently when under heavy load, mostly when rendering models in Redshift which uses both GPUs (full build below). When I disable my second GPU, the freezes do not happen anymore. Especially considering how power-hungry the 3090 is (and this PC has two of them), this leads me to believe that the issue is with the power draw, but I could be wrong. The motherboard's instruction manual recommends for dual GPU builds to connect a supplementary PCIe Power Connector cable from the power supply to the motherboard, but I'm having trouble finding the correct cable. Any help is greatly appreciated.

Photo from motherboard's instruction manual: https://postimg.cc/WhtfSmhy

PC Build:
CPU: AMD Threadripper 3990X 2.9 GHz 64-Core Processor
CPU Cooler: NZXT Kraken Z73 73.11 CFM Liquid CPU Cooler
Motherboard: Gigabyte TRX40 AORUS XTREME XL ATX sTRX4 Motherboard
RAM: G.Skill Trident Z RGB 128 GB (4 x 32 GB) DDR4-4000 CL18 Memory
Storage: Samsung 980 Pro 2 TB M.2-2280 NVME Solid State Drive
GPU: Asus GeForce RTX 3090 24 GB STRIX GAMING Video Card x2
Case: Corsair 780T ATX Full Tower Case
Power Supply: Corsair AXi 1600 W 80+ Titanium Certified Fully Modular ATX Power Supply

Hmm not sure. Looks like the cable you posted would fit, but not sure where the other side would go.

Here's a pic of the "OC_PEG" port on the mobo:


For the power cables going directly into the graphics card, each GPU takes 3x8 pins.

SOLVED: AMD Threadripper 3990X 2.9 GHz 64-Core Processor only supports up to 3200 RAM speed which is likely what was causing the freezing. Also found the cable I was looking for:
https://www.corsair.com/us/en/Categories/Products/Accessories-|-Parts/PC-Components/Power-Supplies/Type-4-Sleeved-black-PCIe-cable-with-pigtail-connector-and-capacitors-for-Type-4-PSU/p/CP-8920143