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shmerek Mar 7, 2000 07:02 PM
OS ram requirements
I have OS 9 on my iMac and I just installed 128 MB of ram so I have a total of 160. I turned off virtual memory and now when I run a couple of programs my OS eats up between 40 to 60 MB of ram. I was running Photoshop and Golive at the same time and the OS was taking 58 mb is this normal?
James Z Mar 7, 2000 07:09 PM
That is normal.
MacPhan Mar 7, 2000 08:46 PM
Unfortunately I have to chime in with James. I'm running OS 8.6 and right now, with only internet programs running the OS is eating up 56.5 MB....SUCKS. I just installed another 128MB from Crucial. Thank God the prices dropped. I'm reminded of my PB100 with 4/40... Ahhhh, the good (?) old days!

secretsquirrel Mar 7, 2000 11:12 PM
I agree that Mac OS memory consumption raises a few eyebrows. Bear in mind the following though:

- turning off virtual memory causes more ram to be consumed by everything, because you lose the efficiencies that VM brings in program code loading. Expect a 10-25% jump im memory use per application.

- adding more physical memory causes MacOS to use more for the disk cache unless you tell it otherwise. Open the Memory control panel to see this setting.
The Wolfe Mar 7, 2000 11:30 PM
yes, the Mac OS may be taking up 50+ MB of memory when you have 160MB of RAM because the computer has that much memory to play with. Starting with Mac OS 8.1, the system started showing everything that was bundled into the memory heap. If you're only using a few apps, and there is plenty of free RAM, who cares if the Mac OS uses 50+ MB. Of course if you open up more or bigger apps and you need the memory, the Mac OS will allow other apps to use it.

It's a poor way to display memory usage, but oh well.
Lazeruus Mar 7, 2000 11:38 PM
All, my freinds, will be well as it was in the best days of your exp of mac computing.
(dark landscape of thick clouds parts way as rays of bright sun bring forth a grand box of joy)
Ahh the glory of OS X.
iMan_ca Mar 7, 2000 11:49 PM
You should leave VM on, you could crash more often. Most programs the memory Partition is set as low as they can. They don't expect people to be running with VM off. With VM off the program needs more memory and will run out. The other option it to increase the memory partition of each program. An iMac with 128+ memory can run very well with VM on.
The OS is designe daround it being on, unless you are making movies leave it on. Programs take longer to load up (more to load into memory) and programs use more memory. Advantage of VM being off, if you have alot of programs open 10+ they will run faster then if you have VM on, less disk activity.
I have more then enough to turn it off, and I got a older mac that does not use memory for the ROM and stuff but I leave VM on cause it ended up being better.
Yes the OS takes more memory with more porgrams open. Different programs calls for things from the OS, and extra services, EX Useing internet Explorer also starts up PPP and OT and stuff. They show up in the system heap.
shmerek Mar 8, 2000 09:01 AM
I was under the impression that your computer would run slower with VM on, is this assumption incorrect?
Misha Mar 8, 2000 09:57 AM
The Mac will run slower with VM on. If you have enough RAM to turn it off, do so. You won't crash any more times with it off (just like you won't crash any less), and if apps start griping for more RAM, just quit them and give them more, then fire 'em back up.

My iMac DV purrs with 256 MB and VM off. I crash twice a week at most, and that's usually while running a dozen apps and plenty of third-party extensions/control panels (no, I'm not saying my iMac is any more stable because of the extra RAM).
pscates Mar 8, 2000 11:11 AM
I dropped a 128MB DIMM into my iMac DV a few days after I bought it, for a total of 192. It was just enough to run Illustrator, Photoshop, GoLive, ImageReady, a browser, ATM Deluxe at the same time at their suggested settings (I HATE opening and closing programs when I'm trying to do something that involves using several of them).
So I finally said "what the heck" and took out the stock 64MB and dropped a 256MB DIMM in its place. Now I have 384MB...PLENTY of headroom and I was able to give all these apps a little extra playroom.
But you know what? Even before all this, I NEVER crashed. Granted, all I could run with 64MB was Explorer or Outlook Express. But I never use VM, especially now.
It's so nice to have 6 or 7 Adobe apps up and running, bouncing back between them all AND still have about 60-70MB of memory left over. Overkill? Perhaps. But with OS X on the horizon and apps only getting more RAM greedy, it's nice to know that I'll probably never have to buy RAM again (or at least any time in the foreseeable future).
BTW, at home my system takes up about 60MB. I use a G4 at work and it hovers around that same amount as well (it has 384MB RAM as well).

[This message has been edited by pscates (edited 03-08-2000).]
Vsx1 Mar 9, 2000 08:23 AM
i bought my iMac with 128 MB installed and i turn off VM. HD are the slowest component on an iMac (same goes for any computer) so why store RAM data on the HD if you have the RAM.
With my 128 MB RAM, i can have Adobe GoLive 3.0, Netscape Comm 4.72 but can't open Maple 5.1 cuz there isn't enough RAM. But i can have several apps open at once with plenty of speed.
JayBee Mar 9, 2000 10:15 AM
Does anyone notice the 'big' difference in speed with VM off? I think, as from OS 8.6, there is just a very small speed gain.
dbergstrom Mar 11, 2000 09:48 PM
The biggest differences I've noticed is with changing my disk cache settings. I have a Wallstreet with 160MB of RAM. This means the default disk cache setting is >5 MB. I was consistently having problems with memory fragmentation, even when I was very careful to close applications in reverse order of when I opened them.

Last Saturday, I read on one of the forums that disk cache gives no speed benefit over 2MB. So I went into the memory control panel and scaled mine down.

Now, not only does OS9 eat less RAM, but my meory fragmentation problems have lessened. I used to have to do a restart every 2-3 days to clean up the memory, but now I haven;t restarted since last Saturday. That means no crashes, either.

So, smaller OS footprint, less memory fragmentation, and NO SPEED HIT.

Decrease your default disk cache to 2048KB now!
Lazeruus Mar 16, 2000 03:43 AM
Yes there is a speed gain after 2MB.... whoever said that.. is... well simply wrong. There are trad-offs in how fast read vs. write. I dont know the exact #s but you still see better disk preformance after 2MB.


In Velocity + Mass + Trajectory
You will find the creator,Fate.
John Palmer Mar 16, 2000 11:26 AM
Re: Virtual Memory Usage with OS 8.6

I use a Umax C600 w/ a Sonnet G3/L2 upgrade card. I hated using VM because of the significant performance decrease; the hard drive was always running (48M RAM). I used Connectix Ram Doubler for years with great performance, and then bought the G3 card and another 32M, thinking I could delete Ram Doubler. I had heard that Ram Doubler was on its way out with the changes in Mac OS.
Well, I tried running Quark and Photoshop and Canvas in various combinations without VM and had constant crashes. Re-installing Ram Doubler reduced the system heap, app. reqts., etc, and eliminated the crashes.
I recommend using Ram Doubler instead of VM.
iPond317 Mar 16, 2000 08:00 PM
Okay, if lowering the Disk Cache will decrease the RAM requirements for OS 9, what should I set it for if I have 224 MB? Every time I want to edit the Cache, the Memory control panel tells me it could screw up system performance. What should I set it on?

-- iPond317
All hail iMac DV
G4 Performance Leader
iBook #1 consumer laptop
Mac OS 9: Your Internet co-pilot
Power Mac G4 considered "super computer"
Think different.
wlonh Mar 16, 2000 08:16 PM
for what it is worth, Apple recommends you allow the default setting to be made. they claim that this default setting is optimum.

it seems so for me.

it is calculated according to how much RAM you have, total. it is therefore a custom setting even though it is made by default

[This message has been edited by wlonh (edited 03-16-2000).]
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