Quick question about ram!

No its not true.
Sometime adding more RAM may not give you a noticeable boost,but it won't make your performance worse.
For example,going from 4GB to 8GB RAM won't give you much of a difference in games but it doesn't make them run slower either.

That was true in some cases 5 - 10 years ago but not true now. Technology has superseded your teacher's knowledge in this case.

I see thanks for the responses guys, that answers my question.

So I can load my RAM slots.. going to steal this thread real quick.

I have been debating on going 12gb with 6x2 or 3x4. Yeah yeah I know I don't need 12gb. So you are saying filling the 6 slots won't hinder me at all? even in overclocking? I want to run an i7 950 to 3.5-3.8 no more than that on a msi big bang xpower. I also want g.skill 1600 ripjaws. I have been debating getting this 12gb(3x4) set or 2 of this 3x2 set. The 3x2 set would match my MB better than red and would save me $65.
So, are you saying that filling the RAM slots will not effect my overclocking either?

^The only (2) times where it is true: 1. 32-bit OS > 4GB, and 2. Channel Configurations: Hexa-Channel vs Tr-Channel - Tri FASTER = {3 X 4GB} then hexa {6 X 2GB} and similar with Dual-Channel - FASTER {2 X 4GB} vs {4 X 2GB}.

So your Teacher is right in some regards, and it depends upon his/her context of the statement.

One more question, if I were to run 3 sets of this 2x2gb cl7 ram, is there a possibility that they will not run at the stock 7-7-7 settings? there is also this set for $20 cheaper at 7-8-7.

^ In general lower CAS per same speed is faster.
7-8-7-24-2N is slower than 7-7-7-24, but most important question is it compatible?

However, most people make a critical error of either not choosing Certified {per MOBO spec'd} or Tested {per RAM Mfg} DDR. Therefore, you'd need to specify your exact MOBO before anyone could answer any question of DDR3 RAM and in particular if it will work.