This is my first PC build, and I'd like a compatibility check before buying everything. The planned parts are a Gigabyte X870 AORUS Stealth motherboard, Ryzen 9 9900X3D, Gigabyte Radeon RX 9070 XT, 32GB (2x16GB) Corsair Vengeance RGB DDR5-6000, Samsung 990 PRO 2TB PCIe 4.0 NVMe SSD, Lian Li Hydroshift II LCD-S 360mm AIO, Corsair RM850e 850W ATX 3.1 power supply, and a Lian Li V100 ATX mid-tower case with four 120mm ARGB fans. Will these components work together, and am I missing anything important?
2 Answers
The 9900X3D is a reasonable choice, but it may be more CPU than you need for gaming. A Ryzen 7 9800X3D or another lower-core-count X3D chip could offer similar gaming performance for less money, unless you also plan to use the extra cores for rendering, streaming, or other heavily threaded work.
The core parts should be compatible: the X870 board uses the AM5 socket, the DDR5-6000 memory and NVMe drive are appropriate, and an 850W ATX 3.1 power supply should be suitable for this CPU and graphics card. Before ordering, double-check that the V100 supports the AORUS Stealth motherboard’s rear-connector layout and that it has room for a 360mm radiator in your preferred mounting position. You’ll also need an operating system, and it’s worth confirming whether the cooler includes the correct AM5 mounting hardware.

I don’t strictly need the extra cores, but the 9900X3D was only about $100 more than the 9800X3D, so I figured the additional performance and flexibility might be worthwhile.