I have a laptop inside which there were two 1 GB RAM's, making a dual channel.
It took about 18 sec to open a 200 MB ppt file.
Today I put one 2 GB RAM instead of the dual channel above. It took about the same time to open the ppt file.
Now I added one of the 1 GB RAM's, making a total of 3 GB. This time it took about 50 % longer to open the same file. Iin other words it took longer with more RAM!!!
I replaced the 1 GB RAM with another 2 GB RAM, making a total of 4 GB. This time it took about the same time with 2 GB RAM. This little machine can use only 3 GB even with 4 GB.
what OS are you running? it only takes so much ram to boot, just say; 1/2 a gig, so adding 3 gig won't do any better then 1 gig while booting up but when running multi-programs is when you will see it affect your computer as in "speed"
Maybe that the speed of the ram isn't the same? If you have a 800 mhz effective ram stick with a 667mhz ram stick, the difference in speed will cause it to lose bandwith because the other memory stick has more bandwith, needing to wait for the 667. With 2x1 gb sticks, they go into dual channel, that dual channel make it almost double the bandwith