I’m looking to add some RAM to my laptop. The prices vary quite a bit. Does the quality vary, or are they all the same?
If the former, which brands are good and bad?
My personal experience with cheap RAM off ebay is yes, cheap RAM can suck as does the service you get from the sellers :mad: 
:mad: :mad:
Since this one is gonna involve opinions, let go to IMHO.
samclem General Questions Moderator
My experience is that brands make the most difference if the memory goes bad. With el cheapo ebay memory, you’re usually SOL. If you buy from Crucial, Corsair, or Kingston, you will have excellent warranty service if your memory fails.
Another thing to consider is what you’re going to use the memory for. If you’re going to be doing a simple memory upgrade, then the most inexpensive lines of memory (within those brands) are perfectly functional and are really quite cheap. For example, I upgraded the RAM in my new Macbook Pro to 4gb of Crucial memory for $109. If you are a high end gamer that makes it a hobby to overclock and squeeze maximum performance out of your hardware, then you can expect to spend hundreds of dollars for a couple of gigs.
I suggest you go to Crucial and enter your system in the Memory Advisor tool and see if the price fits your budget.
If you buy really cheap no-name memory, you run the risk of getting something that is made from substandard or defective parts. I’d stick with branded memory from a company that has a decent return policy and warranty.
Aside from obvious memory-related problems, can bad RAM hurt other system components? That is, can bad RAM send such wrong information to the drive that it corrupts the FAT (or other crucial sections)? Can bad RAM fry the motherboard?
I’ve never tried buying off ebay, but in my experience there’s no such thing as cheapo ram. On newegg there’s stuff like Kingston Value and there’s other brands, but they all cost essentially the same and use essentially the same components. (The brands don’t make chips, they just solder them to the little boards.) Anything on newegg.com should work great (but read the reviews anyway).
There is, tho, a 2nd type of ram. It is call Idiot Poser RAM. It costs 2-3x as much and does absolutely nothing. EVEN if you are overclocking, it is close to worthless.
Yes, bad ram can definately corrupt data but it’s a matter of probabilities. It usually doesn’t happen unless the ram is very error-prone but reinstalling the OS and apps can be a good idea after discovering your RAM was bad.
Bad ram will not, however, fry a motherboard. The only thing possible is that if you flash your firmware you may write incorrect data. However, simply on its own, computer components very rarely cause cascading hardware failures.
For completeness, I should mention that the motherboard itself may have a problem that it won’t like some types of ram. This is actually the case with my current (cheapo) board. It used no-brand sticks just fine but Kingston actually barely worked (until I enabled memory tri-stating in bios). However, this is really just advice to not buy iffy motherboards.
I would stick with PNY or another major brand, were I you.
The quality vendors test their RAM more before it is allowed to leave the factory. Cheapo RAM may work great forever, it may introduce errors that are impossible to isolate to any particular component, or it may just die within a year.
The best bet is just to buy a quality RAM from manufacturers like Kingston and be done with it.
It can definitely corrupt the data on your hard disks, including the file directories and system areas. Data buffers can be corrupted before they are written to the disk, and systems that crash a lot often corrupt data on the disks.
If there’s a really serious problem, like a short-circuit in a memory chip, it’s possible that it could damage chips on the motherboard. That sort of thing, thankfully, is rare.
RAM is so cheap anyway that you may as well get name-brand. I just bought 2 gigs of Crucial for $39.99 this weekend.
Ditto