As I mentioned in the introduction of this chapter, way back in the dark ages of the PC architecture, I once owned an original Compaq portable. I upgraded my Compaq myself with an additional 384KB of memory by carefully inserting 27 individual 16KB RAM chips.
RAM now comes on tiny circuit boards.
If the 486 system will take SIMMs, you must only add them one at a time. Pentium systems using the 430FX and 430NX chipsets accept SIMMs only. The 430NX systems, aka Neptune chipsets, were the first PCs to use EDO memory. Pentium, Cyrix, and K6 systems using the 430HX, 430VX, and 430TX systems can accept SIMMs or DIMMs. Note that the vast majority of 430HX systems are SIMM only.