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With two user accounts running simultaneously with fast user switching, is there any issue in running say 10 apps simultaneously in each account?

I have a personal setup and one I use for when I'm at work so that I can create two full workspaces that have different accounts/preferences, etc. But I like to be able to fast user switch between the two. In each account I have Mail, iChat, Reeder, Safari, Skype, iCal, iTunes, iWork open all at the same time. I used to do that on my old Macbook, but I would only have one account logged in at a time. Now with my new Macbook Air, it seems so far that it's ok handling all of those apps running at the same time in both accounts.

Can someone explain to me exactly how it's managing all of that memory and resources and what performance (battery?) issues I might encounter. Is there a generally recommended limit to the number of simultaneous processes for a machine with 4GB of RAM, when those processes are pretty basic?

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closed as not a real question by Jason Salaz, Loïc Wolff, patrix, Nathan Greenstein Dec 8 '11 at 14:59

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Exactly how it's managing all that memory? You're probably only going to be able to get that from someone who helped develop the OS X kernel. :) Seriously, though, it's unlikely you'll get valuable, specific numbers here. You've asked a complex question with no straightforward answer. – Dan J Dec 8 '11 at 4:23
This question isn't really a good fit for this site. There are many, many things that influence how many apps you'll be able to run, so it will be hard to get specific answers. Please take a look at the FAQs for more info. Thanks. – Nathan Greenstein Dec 8 '11 at 14:59
I read over the FAQ, I understand the need for order and refinement, but I'm unsure how this question doesn't fit this site. It's a question about Apple Software/Hardware, I'm looking not for someone's opinion or a general casual question. I'm looking for an answer to a Apple computer usage question. I basically want to know the recommended or expected workflow on this machine. If I can't ask that question here, where else can I ask it? – drury Dec 8 '11 at 16:32

There are no system resources that can meaningful be counted in "applications", but some programs hog system resources atrociously, while others use hardly any.

If your computer seems 'burdened', then run activity monitor to learn what processes are using the most CPU and RAM, especially processes you aren't actively using. You should avoid leaving badly behaved processes running continuously.

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This is essentially the answer I was writing when SE told me that an answer had been posted. The important issue is CPU/RAM, not "number of apps." The apps you have listed will have a negligible effect on the computer when not actively doing something. Now if you were converting audio/video on both accounts, that would be different, but no different than if you were trying to do multiple conversions on one account. TL;DR: "apps don't matter, CPU/RAM usage matters." – TJ Luoma Dec 8 '11 at 8:00
If this is the case, then when I look in Activity Monitor what should my average CPU and average RAM be? In other words, besides experimenting day after day with battery life, is there a way to find a sweet spot for operation? Am I aiming, for example, for no less than 90% idle CPU and at least 500MB Ram Free? – drury Dec 8 '11 at 13:00
There isn't any fixed number here either because resources exist to be used. Activity monitor simply identifies the culprit if your system slows down. Safari using 99% CPU is fine if your using Safari. Safari using 15% CPU might be too much when not browsing the web. – Jeff Burdges Dec 8 '11 at 13:35
There are various system tasks like mdworker that must periodically run for spotlight, time machine, etc., which can consume lots of CPU resources for a short time. If you see anything really using considerable CPU, then google can tell you what it does and what application created it. Don't just rush off and kill it thinking it's a virus or something. – Jeff Burdges Dec 8 '11 at 13:47
So what I'm gathering from this is I should just keep everything open that I use on a daily basis in both accounts and wait and see what it does in terms of performance. as long as things I'm not using aren't hogging resources in the background and my battery life isn't suffering too much the computers resources should be used to the max if I need max usage. Yes? – drury Dec 8 '11 at 14:43

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