To clarify, you have enough memory. You can run all of PrimeGrid's apps comfortably in 16 GB. Simply having more memory won't make things faster.
However, depending on the exact configuration of your motherboard, adding additional memory sticks may improve performance. This is because, under the right conditions, your computer can use multiple sticks of memory simultaneously. This essentially increases the speed of the memory in your computer, and for the Generfer and LLR apps memory speed is very important.
You'll have to tell us more about your computer: What kind of motherboard you have (make and model), the CPU model, the number of memory sticks you already have, what speed they are, and which memory slots they occupy on the motherboard. With that information, we may be able to tell you whether adding additional memory will be beneficial.
In particular, if your motherboard is currently accessing memory in single-channel mode, and adding a second memory stick allows it to operate in dual channel mode, then you may see a noticeable improvement in performance. However, if your motherboard is already using all available memory channels, adding more memory will not improve performance.
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