I live in Chile and am building a gaming PC around a Ryzen 7 7800X3D, mainly for Rust and Arma 3. I found an open-box 2×16GB DDR5-6000 CL30 kit that would cost about $480 after shipping, compared with $360 total for two 2×8GB kits of DDR5-6000 CL38 from a local reseller. The 4×8GB option is $120 cheaper, but I keep seeing warnings that four DDR5 modules can be harder on the memory controller and may require lower speeds or looser timings. Could instability or reduced 1% lows and microstutter make the more expensive 2×16GB kit worthwhile? I'm inexperienced with PC building and would appreciate advice on the likely real-world difference.
2 Answers
I’d lean toward the 2×16GB kit. Four DDR5 sticks put more load on the memory controller, so the advertised 6000 MT/s may not be stable—especially when mixing two separate 2×8GB kits. You might have to reduce the speed or loosen the timings, and that can hurt performance consistency more than average FPS. The 2×16GB kit is also a matched kit with better timings, making it the safer choice for a 7800X3D.
For Rust and Arma 3, smoother frame times can matter more than the average FPS number, so I wouldn’t ignore the possibility of microstutter. Four modules might work, but there’s no guarantee they’ll run at their rated settings, and mixing kits is less reliable than using one matched 2×16GB kit. The extra $120 is a lot, but it buys a more predictable setup and better CL30 timings.

You could try the cheaper 4×8GB setup first and run proper memory stability tests. If it isn’t stable at 6000, return it and buy the 2×16GB kit instead. Just make sure the store’s return policy covers compatibility issues.