I'm upgrading my five-year-old AM4 system in the Netherlands and would like the new platform to last another five years. My main use is gaming at ultrawide 1440p, especially CPU-heavy simulation games such as Cities: Skylines and Transport Fever 3, where strong single-core performance and good performance in large, complex simulations matter.
My current system has a Ryzen 5 5600X, Arctic Freezer 36 A-RGB cooler, 32 GB DDR4-3600 CL16, an RX 9070 XT, several SSDs, and a 760 W Fractal Design Ion+ Platinum power supply. I'm planning to replace the CPU, motherboard, and memory with a Ryzen 7 9800X3D, an ASUS TUF Gaming B850-PLUS WiFi, and 32 GB of DDR5.
For memory, I'm choosing between DDR5-6000 CL30 and DDR5-6400 CL32. The 6400 kit is cheaper, but I've heard AM5 systems are often easiest to run around DDR5-6000. Can the 6400 kit generally be downclocked to 6000, ideally without much manual BIOS tuning, or is it better to pay more for the 6000 CL30 kit?
Is the B850 motherboard a sensible choice for its connectivity, M.2 support, PCIe 5.0 support, case I/O, and overall quality? Also, is the 9800X3D worth choosing over the less expensive 7800X3D for simulation games and long-term use? I'd like to keep the existing cooler and power supply if practical, although I can upgrade the cooler later if temperatures require it.
2 Answers
Be realistic about the game engine rather than expecting any single CPU to solve every performance problem. Cities: Skylines II, in particular, can become extremely demanding as a city grows, and even high-end processors may experience frame-rate drops. A 9800X3D is a strong choice for simulation-heavy gaming, but the improvement over a 7800X3D may not justify a large price premium unless you specifically want the extra performance and longer-term headroom.
The existing Freezer 36 should be usable initially, provided the correct AM5 mounting hardware is included and temperatures are reasonable. Monitor temperatures and sustained clock speeds after installation. Your 760 W quality PSU should also be adequate for a 9800X3D and RX 9070 XT, assuming it is in good condition and the GPU power connectors are installed correctly.
The DDR5-6400 kit is probably worth considering because you can usually select 6000 MT/s manually if its default profile is unstable. At that speed, you may also be able to tighten the timings, although the exact result depends on the memory kit, motherboard, BIOS, and the individual CPU’s memory controller. Start with the rated profile, then try 6000 MT/s if necessary; avoid adding voltage unless you are comfortable testing stability.
For the CPU, compare benchmarks using the specific simulation games you play. The 7800X3D is still an excellent gaming processor, but simulation games can be much more CPU-limited than typical shooters, particularly with large cities or many simulated entities. The 9800X3D can make sense if the price difference is acceptable and you want the best gaming performance available on this platform, but it will not eliminate performance drops in especially poorly optimized games.
That makes sense for the memory. My main concern is whether dropping the 6400 kit to 6000 is likely to work without a lot of manual tweaking. I’m also taking the simulation workload seriously because thousands of agents can be more demanding than a typical competitive shooter.
Cities: Skylines II is not my main priority at the moment because its performance is still heavily affected by the game itself. I’m focusing more on Transport Fever 3, where a stronger CPU should be useful as the simulation grows.