Chip part numbers do not always follow any pattern, manufacturers tend to form a naming style but this is not always true. Often it is difficult to describe the patterns they are so random, but as you become familiar with IC part #, You begin to see the patterns more easily. This page lists some patterns and techniques for deciphering the part numbers; however, there are no rules, so these hints will not work in all cases.
There is a lot you can learn from a chip before event looking at the part number.
Manufacturers tend to focus on certain sectors of the IC business, and avoid other sectors. So identifying the manufacturer can bring you a great deal closer to its function. If there is no logo, the manufacturer can often be found in the part number itself. See the Manufacturer Prefixes Section
The chip package can also give you hits as to its function.
If you know the function of the board your chip is on then you know what basic functions chips on the board would have to perform.
A computer motherboard would generally have a CPU, maybe a FPU, a bios chip, cache memory, and a few bus controllers.
Narrowing down the different functions of each chip on the board can help you guess your chips function.
Deciphering a chip's part number is a very ambitious process and most of the time, typing the whole part number in a search engine gets you nowhere.
The quickest way to identify the chip is to identify that it is a member of a IC family. By identifying the family you find the function without worry about prefixes and suffixes.
Read the full answer on the HowTo Wiki.
This question was asked on The HowTo Wiki.