Question Please help

Nov 16, 2020
So im building my first ever pc and my roomate has kinda helped me hes built one before. Its all together and it won't show up on the screen everything turns on ive checked the connections everything is snug, and still no display, using the io on my mother board or the connections on my graphics card. Parts below.
Seagate IronWolf 8TB NAS Hard Drive 7200 RPM 256MB Cache SATA 6.0Gb/s CMR 3.5" Internal HDD for RAID Network Attached Storage ST8000VN0022 - OEM
AMD RYZEN 9 3900X 12-Core 3.8 GHz (4.6 GHz Max Boost) Socket AM4 105W 100-100000023BOX Desktop Processor
WD Blue 3D NAND 1TB Internal SSD - SATA III 6Gb/s M.2 2280 Solid State Drive - WDS100T2B0B
CORSAIR RMx White Series RM850x White (CP-9020188-NA) 850W 80 PLUS Gold Certified, Fully Modular Power Supply, 10 Year Warranty
G.SKILL Ripjaws V Series 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600) Desktop Memory Model F4-3200C16D-32GVK
ASUS Dual Radeon RX 5600 XT DUAL-RX5600XT-T6G-EVO 6GB 192-Bit GDDR6 PCI Express 4.0 HDCP Ready CrossFireX Support Video Card
DIYPC Vanguard-V8-RGB Black Dual USB3.0 Steel/ Tempered Glass ATX Mid Tower Gaming Computer Case w/Tempered Glass Side Panel and Pre-Installed 4 x RGB LED Dual Ring Fans (7 Different Color in 3 Mode Control
In chronological order...

First, recheck all of your hardware installation, specially ensure the thermal paste and cooler installation is properly done. Also make sure you are connecting the screen to the card and not the motherboard.

Second, some Asus boards have issues with the 1st GPU slot on first boot as the cpu is trying to recognise drivers for a GPU that doesn't exist yet. So, move the card to the lower slot and see if it fixes the issue, as it uses the chipset driver which has universal GPU support. You can move the card back once the computer has booted for first time.

Third, if the above does not fix the issue, then the board might be lacking BIOS ver. 2605 or above for Ryzen 3000 support, in which case you will need a Ryzen 2000 processor to upgrade the BIOS, as that board doesn't have FLASH Bios option.

Fourth, if all the above is fine, then there could be memory compatibility issue and you will have to test with substitutes.

If all the above fails, then you simply have a bad board or CPU and you have to RMA whichever it is.

On a side note, at this point of time with so many b550/x570 boards within similar price range of that b450, going with that board was a bad idea.