GPU Shutting Down Shortly After Post

[iPC]

Hi, I recently did a new custom watercooled build. However, when I turn it on, after about 20 seconds, the graphics card shuts down. The rest of the computer is still running, but I don't get any video output. Error LED appears to be on boot devices (green). Here's the specs (3rd rad didn't work out): 

PCPartPicker Part List

Type	Item	Price
CPU	AMD Ryzen 9 3900X 3.8 GHz 12-Core Processor	$499.99 @ Best Buy
Motherboard	Asus ROG Strix X570-I Gaming Mini ITX AM4 Motherboard	$249.99 @ B&H
Memory	G.Skill Trident Z RGB 32 GB (2 x 16 GB) DDR4-3200 Memory	$134.99 @ Newegg
Video Card	NVIDIA GeForce RTX 2080 SUPER 8 GB Video Card	$699.99 @ Best Buy
Case	Phanteks ENTHOO EVOLV SHIFT Mini ITX Tower Case	$109.99 @ Amazon
Power Supply	EVGA SuperNOVA GM 650 W 80+ Gold Certified Fully Modular SFX Power Supply	$109.94 @ ModMyMods
Case Fan	Corsair ML120 75 CFM 120 mm Fans	$30.99 @ Amazon
Monitor	Dell AW3418DW 34.1" 3440x1440 120 Hz Monitor	$749.00 @ Amazon
Custom	Prolimatech PRO-USV12-BK Ultra Sleek Vortex Case Fan (BLack)	$18.99
Custom	XSPC EX120 Single Fan Radiator	$39.99 @ Amazon
Custom	XSPC EX120 Single Fan Radiator	$39.99 @ Amazon
Custom	EK Water Blocks EK-Velocity AMD CPU Water Block - Nickel + Acetal	$88.95 @ Amazon
Custom	EX950 2TB	$209.99
Custom	WB GPU	$123.99
Custom	RAD 1	$35.49
Custom	Tubing	$14.99
Custom	Coolant	$19.99
Custom	Pump	$189.99
Custom	T-Splitter	$8.99
Custom	Ball Valve	$16.99
Custom	6mm Extender	$2.99
Custom	Fittings x16	$95.84
Custom	EXP 90 Degree x4	$35.96
	Prices include shipping, taxes, rebates, and discounts
	Total	$3528.01
	Generated by PCPartPicker 2019-12-07 22:17 EST-0500