I was wondering if anyone could validate this statement:

PC uses RAM more efficiently. What may be 4GB of RAM on a MAC G5 is equivalent to 2.5 maybe 3GB RAM on PC.

A friend of mine was trying to explain to me that the MAC does not use RAM as well.

He sent me a screen shot of his computer running 30 applications (including photoshop, lightwave, modeler, illustrator, aftereffects and many more)... he is using just 1GB on a PC and the screen shot shows 50% ram usage.

A friend of his had 512MB ram on a 2.0 g5 and his systemn crashed after three applications and a calculator.

Any ideas? Is my 2GB of ram in my G5 really not running like 2GB on a PC?