Just so you know ram is 1000 times faster than SSD and 100,000 times faster than your HDD.
The performance of a computer system is related directly to its execution time.
The execution time is given by CPU time = IC * CPI * Clock period
IC = number of instructions executed
CPI = average clock cycles required per instruction
When you start doing swaps you will experience timeouts while waiting for a memory resource due to slow swaps and overall increase in query execution time, drop in active queries hence bottleneck your cpu (cpu spikes).
So to avoid such issues, upgrade the ram.