What does + in the memory type of DDR4 RAM mean?
Solution 1:
The "+" usually indicates that the motherboard supports RAM with a frequency of over 3000MHz. The OC in brackets means that the motherboard allows the RAM to be overclocked. The caveats being that you may need to increase the voltage and/or the timings in order to accommodate the higher frequency.
This article provides a good explanation on memory timings (e.g. 9-9-9-24):
Memory Timings/Latency Expalined