Should I use 32GB of 3200MHz RAM or 48GB at a lower speed?

For gaming, I’d stick with 32GB at 3200MHz unless you regularly use more than 32GB. The extra capacity only helps when your system would otherwise run out of memory and start paging to storage. If you never reach that point, the faster, lower-latency setup is generally preferable, although the real-world gaming difference may be fairly small.

Make sure the two 3200MHz sticks are installed in the recommended dual-channel slots, usually A2 and B2. In the BIOS, enable the correct XMP or memory profile and verify the reported memory speed afterward. If all four sticks are installed, the motherboard may automatically lower the speed for stability, and mixed kits may not run at their advertised settings. Also remember that some monitoring tools show the actual clock, which is half the effective DDR speed—about 1600MHz corresponds to DDR4-3200—while 2133MHz usually indicates the default safe setting.

It depends on how you use the computer. Gaming and everyday use usually don’t need more than 32GB, so the faster pair is a good choice. If you’re editing video, running virtual machines, keeping lots of applications open, or otherwise exceeding 32GB, 48GB may be more useful even at a lower speed.