Probably a silly question - memory

[cbl2001]

Hi all,

I have a 15" PBook G4 1Ghz with 512MB of memory. Im using panther, and for my course I have to do a lot of video, graphic and web work. Im thinking of upgrading the memory to 1GB, as I know memory upgrades have a good impact on PC hardware - does the same apply to the mac? I.e. am I likely to see a decent speed improvement with the additional 512MB, or is it worth saving my money!? (and aiming for a dual G5 powerbook..

Thanks,
Chris

www.chrisblunt.com

 

[Cheryl]

Additional memory is always a good investment. And you will see an improvement. Go for it !

 

[Zammy-Sam]

Are you sure you have 1x512mb in your powerbook? If you have 2x256mb (what is more common) you might want to replace one 256mb to 512mb which will give you 768mb of total memory.
And I can second the good thing about additional memory. Giving you one example: my tibook has 768mb Ram and after a regular day of work, I just have around 50mb free memory... My ibook turned to a real roadrunner when I upgraded 128mb to 640mb!
And one more good thing: your battery duration will increase since there is much less disc access.

 

[dagaz]

Giving you one example: my tibook has 768mb Ram and after a regular day of work, I just have around 50mb free memory...

I think you are confusing inactive RAM with not available. To see how much RAM is available you should add inactive and free. e.g. at the moment I have 50.0M wired, 100M active, 181M inactive, 331M used, 181M free, so although top reports I only have 181 MB free, I actually have 362 available (not being used by active processes). The more RAM you have the higher the inactive RAM will become in order to speed up the "preemptive multi-tasking".

 

[btoneill]

I think you are confusing inactive RAM with not available. To see how much RAM is available you should add inactive and free. e.g. at the moment I have 50.0M wired, 100M active, 181M inactive, 331M used, 181M free, so although top reports I only have 181 MB free, I actually have 362 available (not being used by active processes). The more RAM you have the higher the inactive RAM will become in order to speed up the "preemptive multi-tasking".

Inactive ram has absolutely nothing to do with preemptive multitasking. Preemptive multitasking is in simple terms, a system that allows multiple applications to share the use of a CPU without having been written to share the CPU.

What inactive RAM really is, is a buffer cache. When an application quits, the OS does not free up the memory that it was using. If you run the same application again, if that memory is still cached in the inactive memory area, your application will start much quicker. The buffer cache also holds filesystem caching data, when you're writing to disk, the data is first written into the buffer-cache, and then written to disk at a later time. This increases disk I/O performance. When the system reaches a preset watermark for "free" memory, it will begin to deallocate memory from the buffer cache, starting with the data that has not been accessed for the longest period until it reaches the watermark to stop deallocating inactive memory.

Brian

 

[Arden]

You will definitely get a speed increase with more RAM. My iMac has 640 MB of memory, and right now the Konfabulator widget says I have only 136 Mb (should be MB, but whatever) free, and that's just with a couple applications open (Safari, iTunes, Konfabulator, Launchbar, and System Preferences. And the Finder, of course). I know, it doesnt seem like much, but that's close to the amount of RAM the iMac came with, and without the extra 512 MB I put in, OS X would be using virtual memory much more extensively, slowing down the system in general.

More RAM is always a good thing. You can never have too much, unless you get like 20 GB.