Precipitates can form when two soluble salts react in solution to form one or more insoluble products - as discussed in the famous example below. The insoluble product separates from the liquid and is called a precipitate. Precipitates can also form when the temperature of a solution is lowered.
When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data is in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than reading from or writing to main memory.
For instance, a 3.1-GHz processor has a clock that beats 3.1 billion times per second. Each clock beat represents an opportunity for the processor to manipulate a number of bits equivalent to its capacity -- 64-bit processors can work on 64 bits at a time, while 32-bit processors work on 32 bits at a time.