How much RAM is enough?

[|MP|Buccaneer]

We were having a talk about how much RAM SK should get for his new G5 earlier on GR today.

A couple people were talking about how 512 and 768 were enough, that 2GB was too much.  

Well, we all know that the more RAM you have, the faster OSX likes it.  And sure, I know that there's a point on that curve where it's not worth buying more.  But where is that point?

I just did a little looking and found this.  This may explain why some of you have trouble with RvS as well.

I'm looking at a dual G4 867 with 1.5GB of RAM.  It's been running for a couple days, and has had a little over 14,000 page outs.  That means it had to read from the disc 14,000 times instead of RAM because RAM was full (or so the story goes).

Hmm, 1.5GB and still using virtual memory.  BTW, it's using 4.2 GB of disc space for that virtual memory (so you guys with less RAM may be using more disc space).

Ok, let's look even more close.  How much is each app running actually using (or blocking off, as the case may be).

kernel is using 99MB
WindowServer is using 59MB
Finder is using 19MB
coreservicesd is using 9MB
SystemUI is using 8MB
Dock is using 8MB
Loginwindow is using 6MB
A bunch of other core services add up to another 46MB

This is not counting stuff like ARD agent, or Palm agent, that are extras.  That means just my bare system is using up ~254MB.  This is actual RAM, btw, not counting the VM they are using.  The kernel that is using 99MB of RAM is also using 790MB of VM.  

So, 256 just to run the core let's say.  Now, I open Safari.  125MB or RAM for that (468MB VM).  hmm.  So if I leave Safari running while I'm gaming, that's another 125MB RvS can't use.

Ok, I like to leave iTunes playing often.  There's another 22MB (154MB VM).  iPhoto started down around 20MB, till I actually used it, then it jumped to 66MB (172MB VM).

I started up JA in server mode.  There was another 100MB without anyone actually playing (I'll need to see if it goes up, I'm guessing yes).

So what does this all mean?

First, the obvious.  It means turn off other apps when you are gaming.  If you are getting page outs, you are going to the disc, and that slows you down.  Give the game as much possible RAM as you can.  I don't know if it will grab more physical RAM, but give it the opportunity.

Second, check your page outs, if you have a lot of them, you need more RAM.  Page Ins aren't as important.

Third, how slow is your HD?  Since you can't turn VM off in OS X like you could in earlier OS's, it's going to access the HD.  The faster your HD, the better.  7200RPM with an 8MB cashe is good.  Don't have a 133 bus in your old computer, you can add a bus card with the HD (since almost all of us have open PCI ports).  Most people ignore their HD speed when they talk about gaming, when it's also related to performance.  For those of you trying to scrape a little more life out of an iMac, yank out those 5400RPM drives (or slower) and put in a nice fast HD.  A 100GB 7200RPM with 8MB cashe will run about $100 on sale at most computer stores.  For those with towers, put in two drives and set up a RAID when you load them.  You'll be amazed how much faster that transfers information.  

The moral of this story is, you really can't have too much RAM, and 2GB is not going overboard.  Add to that, not to neglect your HD when looking at performance.  We can't do a lot about video cards, but we can get enough RAM and a fast HD or two in our machines.  Oh, and remember to always quit Safari.  It's not just a RAM hog, but it's also a CPU hog, even when it's minimized.  

P.S.  Next time I'm running MP Server 2 and it has 16 people on it, I'll try to remember to ssh in and see how much CPU and RAM it is using.  Only way I know how to check RvS is from another machine SSH'ing to it.

[[OZ] Martin]

Hmmm. Just my humble opinion.

I have 1.5GB and have had over 105000 pageouts in 5 days. One problem with your theory is that (to the best of my knowledge) OS X caches everything. Even if you quit an app it may still be in ram. This can be demonstrated by opening apps a second time. First time is slow. Second time is fast. Even if you have ignored an app for days it can still be cached in the memory.

OS X is very different in how it handles memory than OS 9. It will assign an appropriate ammount to the frontmost application if at all possible. Therefore even with 512MB you should still have very reasonable performance. With the exception of the G5's which seem to spike up in some apps (photoshop) once you get above 1.GB or so.

The main problems you'll witness first when running low on memory are serious paging when switching apps or using fast user switching.

cheers

Martin

[Revolt]

how do u findout pageout info/??

[[OZ] Martin]

Type "top" in terminal (in your utilities folder)

you can also type "uptime" to see how long your puter's been running without crash/restart.

Martin

[BFG]

Its very true martin, the 'on second boot' makes a massive difference, you can also get hold of utilities that 'force' all ram and CPU to your front application - it claims to make a massive difference (i tried it and wasn't very inpressed though)

[BTs_GhostSniper]

I have 2.5GB RAM in my G5 and it runs everything just great.  Photoshop screams!

[MainMaN]

my apple II pwns ur g5

[BTs_GhostSniper]

my apple II pwns ur g5

Well, my 128k Mac pwns your Apple II.....it is in like new condition without even the slightest blemish.....I believe at last count it is worth roughly 70 times what your Apple II is worth.

[figuring the 128k Mac at $3500 and the Apple II at $50 for you math wizards out there]

[|MP|Buccaneer]

One problem with your theory is that (to the best of my knowledge) OS X caches everything.

To the best of my knowledge, you are still correct.  However, that accounts for page ins.  It's reading back from the disc that is the real slowdown, the page outs, unless I've read something horribly wrong.

Revolt, instead of using TOP in the shell, you are better off using Activity Monitor in the utilities folder.  You can sort the lists with it's nice GUI interface.

[Jeb]

Unless your doing something like professional dv editing you don't need 2.5gigs of ram, or even more than 1gig. You wasted quite a bit of money GS.

I'd say that only professionals (people who's work depends on creative programs) need more than a gig of ram

[Typhy]

Up until I crashed about an hour ago, I had well over 200,000 pageouts; this from about 6 days uptime, with 1 gig or RAM.

Now, all this time, I'd been compressing video ( MPEG4 ), and of course doing other shit while it compressed.

If you want to be running any background tasks ( video compression, servers, etc ), you'll want to have at least 2 gigs of RAM.

Even in my Dual 1.25 with 2 gigs of RAM ( PC2700 ), I pick up a fair amount of pageouts.

If you plan to use your machine for one thing at a time, 1GB is fine. If you want to have lots of stuff going at once - shoot for more RAM, cheapest way to give yourself a great performance boost.  

[BTs_GhostSniper]

Unless your doing something like professional dv editing you don't need 2.5gigs of ram, or even more than 1gig. You wasted quite a bit of money GS.

I'd say that only professionals (people who's work depends on creative programs) need more than a gig of ram

I wasted quite a bit of money???  I paid $129 for each Gigabite of RAM....that included shipping.  So, I spent a total of $258 for 2.5GB of RAM (it came with 512MB RAM).  Plus, I do a LOT of image editing in Photoshop for work (as we don't have a Macintosh at work, and I REFUSE to work on Photoshop on a PC), so I really do use the RAM....this G5 screams with 2.5GB.

[BTs_Mysterio]

I wasted quite a bit of money???  I paid $129 for each Gigabite of RAM....that included shipping.  So, I spent a total of $258 for 2.5GB of RAM (it came with 512k RAM).  Plus, I do a LOT of image editing in Photoshop for work (as we don't have a Macintosh at work, and I REFUSE to work on Photoshop on a PC), so I really do use the RAM....this G5 screams with 2.5GB.

No offense to you GhostSniper, but you'll find G5s scream with anything over 1GB...

[Supernatural Pie]

I just find it so hard to believe that 1 GB has really become the minimum for what can be seen as "enough" memory.

No more than two years ago, half a gig was more than enough.

Also, just curious, how much of a difference can be seen when it's reading from the disk vs. reading from memory? Is it very noticeable?

Lastly, screw apple for not letting iMac's be upgraded substantially. There I said it.... again....

[Typhy]

Is it very noticeable?

Yes.

[Ace]

So, I spent a total of $258 for 2.5GB of RAM (it came with 512k RAM).

Yeah, but too bad your 8 MHz m68k can only address 16 MB of that RAM.

[Noto]

my apple II pwns ur g5

Well, my 128k Mac pwns your Apple II.....it is in like new condition without even the slightest blemish.....I believe at last count it is worth roughly 70 times what your Apple II is worth.

[figuring the 128k Mac at $3500 and the Apple II at $50 for you math wizards out there]

Oh come on!!!  My Apple Commodore 64 Amiga still runs and it easily owns anything you guys have.  Plus, it has that cool program where it speaks what you type.  Although, you have to type everything phonetically and with some numbers thrown in there.  

.::|N| Noto

[Jeb]

I wasted quite a bit of money???  I paid $129 for each Gigabite of RAM....that included shipping.  So, I spent a total of $258 for 2.5GB of RAM (it came with 512k RAM).  Plus, I do a LOT of image editing in Photoshop for work (as we don't have a Macintosh at work, and I REFUSE to work on Photoshop on a PC), so I really do use the RAM....this G5 screams with 2.5GB.

You would see a major difference in photoshop if you were working on a psd thats 200megs with dozens of layers, paths and some crazy masks...  If your just cleaning up digital pictures you won't see any noticeable difference.  So yes i'd say that you did waste money on 2 "extra" gigs of ram, but don't worry gs thats still better than wasting money on an imac.

I do plenty of freelance webdesign work in my spare time on my g5, and extra ram is essential.
Try using photoshop, dreamweaver, freehand, transmit, cpp, firebird & IE while leaving background programs running, such as peak 4, or even mencoder for kicks. Thats when you notice more than 768megs of ram.
I also use an edit station at work which is a dual 1.25ghz g4 with only 768megs of ram. And work with final cut on projects  that are 10gigs+ of uncompressed dv, and can still maintain great speeds and response.

I'd say for general computer use 1gig is a good ceiling, however if your going to put your computer to the limit on a daily basis buying more won't hurt.

Snipe, an imac is the ford mustang of macs, its for secretaries.

[|MP|Buccaneer]

I just find it so hard to believe that 1 GB has really become the minimum for what can be seen as "enough" memory.

No more than two years ago, half a gig was more than enough.

Two years ago, the fastest mac wasnt half the speed of the current Macs.  Two years ago, standard HD's were smaller too.

Things change.

[|MP|Buccaneer]

I'd say for general computer use 1gig is a good ceiling, however if your going to put your computer to the limit on a daily basis buying more won't hurt.

I'd say 1GB would be the minimum I'd have on a Mac right now.  If I take my mac down to 512, it runs much slower, not even pushing it.  1GB would be my low end with 2GB being my high end.  1.5 being what I have, that sort of makes sense =D.