Less HD space after installing more RAM

how bizarre? sorry, i cant help. but i'm interested to find out the answer.

 

Not sure about what's going on with that situation, but if you want to see what is taking up space on your hard drive I suggest searching google for a program called "Grand Perspective" it's a great program and has helped me weed out the junk on my hard drive.

 

This is completely normal. If you increase your RAM by 2 GB, your available hard disk space will decrease by 2 GB due to the "sleep file" increasing in size. This file is used when your Mac goes into "safe sleep" mode to store the contents of RAM just before shutting it down to save power.

 

^^ You are probably right.

I'm not sure about OSX, but windows has a "page file" that can write information to the hard drive. It is usually proportional in size to your amount of ram.

 

Yeah the sleep file system matches the total size of the installed RAM. So if you had 4GB installed and removed 2, you'd get 2GB HDD back. Also, doubling your RAM like this will make your MacBook take slightly longer than it used to to go to sleep - not ages longer but maybe a second or two - because it has to write twice the amount of information to disk.

 

In Mac OS X "swapfiles" are placed in the /var/vm/ directory.
The default swapfile0 is created on boot, and is only 64 MB in size.

When more HD space is needed for virtual memory (a sign that you probably need more RAM), a 2nd swapfile (swapfile1) is created.
If even more is needed, you guessed it, swapfile2 is made... but this time it is 128 MB is size. The next will be 256, then 512 ... etc.

So, if your Mac has created:
swapfile0
swapfile1
swapfile2
swapfile3
swapfile4
you have used 64 + 64 + 128 + 256 + 512 = 1024 MB (= 1 GB) of extra HD space.
If that were the case doing your "normal" stuff, then get at least 1 GB more RAM.

But back on topic... I think wrldwzrd89 is spot on.