56 minutes ago, BWBriscoe said:

I've taken all of your advice, gone with AMD, so the new setup is:

ASUS ROG STRIX X870-A GAMING WIFI 7 DDR5 PCIe 5.0 ATX Motherboard
AMD Ryzen™ 9 7900X3D, AM5, 12 Core, 4.4GHz, 5.6GHz Turbo 
64GB (2x32GB) DDR5 6000MHz Corsair Vengeance RGB 
32GB GeForce® RTX 5090 Graphics Card
2TB Samsung 990 PRO M.2 PCIe 4.0 NVMe TLC V-NAND SSD
2TB Seagate IronWolf Pro ST2000NT001 NAS Hard Drive, 3.5" HDD, SATA III 6Gb/s, 256MB Cache

Will this increase performance on the previous stated rig greatly?

Please select  any one of the three current gen CPU's .. that 7900X3D (released in 2023) while  a good chip is probably not the best way to go considering the rest of your brand new system.

9800X3D, 9900X3D or 9950X3D.. Those are the current CPU's with an improved implementation of the X3D tech which provides greatly improved thermal headroom, manufactured under a smaller process node and are unlocked. Pick one of the three and depending on your intended use case.

2 hours ago, BWBriscoe said:

I've taken all of your advice, gone with AMD, so the new setup is:

ASUS ROG STRIX X870-A GAMING WIFI 7 DDR5 PCIe 5.0 ATX Motherboard
AMD Ryzen™ 9 7900X3D, AM5, 12 Core, 4.4GHz, 5.6GHz Turbo 
64GB (2x32GB) DDR5 6000MHz Corsair Vengeance RGB 
32GB GeForce® RTX 5090 Graphics Card
2TB Samsung 990 PRO M.2 PCIe 4.0 NVMe TLC V-NAND SSD
2TB Seagate IronWolf Pro ST2000NT001 NAS Hard Drive, 3.5" HDD, SATA III 6Gb/s, 256MB Cache

Will this increase performance on the previous stated rig greatly?

The above will outperform the previous rig (Intel 285).   I agree with and second what @Maxis said, you should strongly consider the latest generation (AMD 9-series X3D cpu) to pair with the 5090 you are getting (nice!)