Can I mix different RAM sizes in my PC?

Yes, you can install a 16GB kit and a 32GB kit together and the system will boot, but you won’t get full dual-channel performance. The memory controller runs in “flex mode” – the first 16GB from each channel runs dual-channel, the remaining 16GB from the 32GB kit runs single-channel. This loses bandwidth, which matters for gaming or video editing. Mismatched speeds and timings cause the system to default to the slower speed, and different voltage requirements can cause instability. It works for basic tasks, but for demanding work, buy matched sticks.