The disadvantages for using "value" or "cheaper" brands is basically the very small chance that you will receive errors when using them or they are not covered by any significant warranty. Generally the way that manufacturers cut costs would be to use lower quality parts and/or designs or to not fully test them. Modules manufactured by the same companies that actually make the memory chips are usually seen as better quality. Memory manufacturers are (or
were in some cases): Micron, Samsung, Hynix, Mitsubishi, Elpida, Infineon/Qimonda , Toshiba, Nanya, ProMos. On the other hand, module
assemblers such as: Crucial, G.Skill, Kingston, Corsair, Kingmax, A-Data, PNY, will buy DRAM on the open market, from various sources, at the cheapest price they can get. Crucial is a special case: they are owned by Micron but will often use other people's DRAM on their modules. "How do you identify a module assembler?". One way to tell is to look at the logos on the memory chips. If it doesn't match the name of the module seller or if there isn't
any markings on them at all, then you are probably looking at a module assembler. Some "performance" assemblers, such as G.Skill and Corsair, will overclock the memory during testing in order to see how fast it can be operated at. However, you usually pay a little bit more money for this type of module.
Lenovo does not make their own memory or modules. They simply "qualify" various modules that have passed their own internal testing so that the buyer is assured that it will work in the computer. Modules that have been factory qualified will have an IBM/Lenovo part number (FRU) label on it. "What's to prevent anybody from putting a fake label on their module?" Nothing, really.
Which comes down to this last piece of advice: Whatever you decide to get, make sure that you test it completely before you accept it. The best way that I know how to do this is to run a memory diagnostic program such as memtest86+. You can download a copy of the program from here:
http://www.memtest.org/#downiso
Let the program run for
at least three complete passes. Doing so will stress the memory system; essentially heating it up. Most memory failures will occur at higher temperatures, although in a few rare cases some errors can be triggered at temperatures colder than room temp. That's usually not too much of a problem unless you are using the laptop outside in the winter
.