Hi, @diller, I suppose you are building your own PC, would recommend you to list out the components, e.g. power supply, computer casing you are using, etc.
Based on the requirement on
Minimum Rainbow Six Siege Closed Alpha PC Requirements:
OS: Windows 7, 8, 8.1, x64.
CPU: Intel Core i5-2500K or AMD FX-8120 Eight-Core.
CPU Speed: 3.3 GHz (Recommended), 2.6 GHz (Minimum)
RAM: 8 GB.
GPU: Nvidia GeForce GTX 670 or AMD Radeon HD 7970 / R9 280 X.
VRAM: 2 GB.
So I guess, your PC is sufficient on it, just that for future upgrades and your computer budget, either to get i7, better computer casing for airflow and better allowing graphic card to fit in, reliable power supply, e.g. seasonic, corsair, antec ... and maybe stretch to 16GB RAM, SSD for OS bootup is fine, you can add additional SATA HDD for misc data storage, for cost consideration.