What are the benefits to having more than 1GB RAM?

Question

I notice the repeated advice in this forum over the question of "Should I get a Matched pair of 2 x 512MB or total 1.5GB RAM in my iMac G5 Rev. A/B?", and the answer always seems to be "more RAM will always perform faster."
Oh yeah, why? Someone point me to an informed link on subject somewhere else on the web. I mean no offense, but I wonder if, in this case, one bit of misinformtion became Gospel truth that keeps getting repeated over and over.
I'm fairly knowledgeable when it comes to Macs, but I don't understand this response that more RAM will always perform faster. Yes, yes, I know that barefeats.com found very little real-world performance gains in their testing of matched pairs vs. unmatched, or 128-bit vs. 64-bit, in the iMac G5. The same would be true of using CL2.5 vs. CL3.0 RAM -- you just ain't gonna see that much difference. But we are not talking processor speeds or hard drive RPM, which WILL affect all users. More memory is just more memory. If you are not using it, what good does it do? How will more unused memory "speed things up?"
I use a neat little program called "Menumeters." It puts my CPU/Disk/Memory/Network activity all in my menu bar. For the memory, it lists USED and FREE memory. Right now on my 1GB Mac Mini it is using 192MB RAM with 832MB FREE with 3 applications open, one of them being Safari.
I recently DOWNGRADED the memory in my iMac G5 2.0GHz from 2GB to 1GB. Why? Because menumeters showed that even in my 2GB iMac, my memory usage never went above about 800MB. Mind you I do video editing in Final Cut Express, I create DVD's in iDVD, I do photo editing in Photoshop, I manage my 8K digital photo library in iPhoto, and I could have all these and other applications open and running and my memory usage never went above 800MB. Every time I have checked my pageouts have been 0, meaning I never had to write the memory contents to my hard drive.
Which begs the question, how is having 1.5 or 2.0GB of RAM going to be a benefit over 1GB of RAM, when I have never needed more than 1GB of RAM in my Mac? I ask because I can either go with 1.0 or 1.5GB of memory in my iMac G5 right now, as I will sell either the 1GB or 512MB memory on ebay. But I'd like to know if someone can give me a compelling reason to put the 1.5GB in my iMac. Otherwise, it just seems like wasted $ to me, as I'll make over double selling the 1GB vs. the 512MB module.
Home: 20" iMac G5 2.0GHz rev.B/1GB/300GB   Mac OS X (10.4.4)   Work: Mac Mini 1.5GHz/1GB/64MB video/80GB

Answer 1

"you are telling me what my needs are based on your needs."
Eric, I have never told you what your needs are or should be. Did I once tell you you were wrong to have 2GB of RAM in your system? No. Did I say it is foolish for anyone to run 2GB of RAM in their iMac? No. Did I say 2GB of RAM in everyone's system would be an unnecessary excess? Certainly. Have you advised people to go for 1.5 or 2.0GB of memory instead of 1GB of memory without doing a needs anaylsis? You most certainly have, here and here and here, even after the original poster states they only want to buy a 512MB module, and in the last example, after someone else in that thread encouraged the novice Mac user to do a needs assessment. I'll let each reader determine for themself which they feel is the irresponsible advise.
Also, I never said "the average user, 'just isn’t going to need more than 1GB of RAM, now, or in the life of his iMac G5'" as you claim I did. I said a person running Safari, Mail, and iPhoto will not need more than 1GB. I consider that a light user. To clarify, to me a light user and an average user are not synonymous. And yes, a light user could get by with 512MB with virtual memory on occassion with an approximate 5% system slowdown, a slowdown which will probably not even be noticable.
What is need? To me if someone experiences an occassionaly pageout does not mean they need to go out and buy more memory. As a comparison, imagine you have a china setting for 12 people you received as a wedding gift. Every Sunday your wife fixes a nice dinner and uses the china. Typically you have 4-8 people at dinner every week, depending on if your brother's family joins you or not. But because of a special occassion -- a graduation that weekend -- you have 14 people at your house for lunch. Do you go out and buy enough china for 18 or 24 people, or do you and your wife use your everyday tableware for yourselves and give the other 12 guests the china that one day and save the expense?
See where I am going? 1.0GB of memory vs. 1.5 or 2.0 compares to 12 china settings vs. 18 or 24. And, no, I am NOT saying you, Eric, should only have 1.0GB of memory, but just if a person's needs dictate that.
Someone might stock the cabinet with 24 china settings when 29 meals out of 30 they have only 4-8 people eating on their china. But someone like myself, and other people that are budget conscious, probably will not want to do that. And I know you can change the illustration to support going for a higher amount of RAM, but my point is that for most iMac users, I do not believe that is something they really need.
Regarding your remark about data manipulation, I am sorry if the facts do not support highway's claims. The point of highway's whole remark was based on the premise that Apple shipped 64MB of RAM as the base amount for an iMac of 4 years ago. I showed where that was not a true statement. How is that data manipulation? And the main point of what I wrote was to show how someone writes an erroneous bit of information, then someone else picks up on that and repeats it, and soon more and more come to believe that misinformation. You can see that going on in these posts here and here with Barbara and here with CanadaRAM, either from misinformation from barefeats, or from others users on this board. Notice no one asking about the poster's needs, but just advice to get a higher amount of RAM.
Again, anyone reading this should do a needs assessment. I noticed, Eric, in your last post you acquiesce about the validity of doing a needs assessment. That's not one small detail. THAT'S THE WHOLE POINT of this discussion. I hope to see less cookie-cutter responses in this forum in regards to memory purchasing and see more responsible advice to determine one's need, especially for the novice users who are asking the questions and won't do any more fact-finding than the advice given them on this board.
I appreciate the advice of those in past threads who have asked a poster to determine their needs in their RAM buying decisions. In my opinion, that is the best advice they can receive. And I am more than done with this topic, as look at how much I repeated information in this last post that I wrote previously.