[Tee]

Not sure exactly how to explain this.

Basically, every file that we download with Safari seems to gobble-up RAM in an amount that corresponds to the size of the file being downloaded. ie. download a 200MB file and we lose 200MB of free memory as shown in Activity Monitor.

This basically means that we can only DL a file that is as large as the amount of free memory that we have available. I can watch activity monitor as the Free memory drops. Once it reaches about 10MB we see massive page outs and system slow downs/pinwheels/disk churning for any action such as accessing menus/switching between apps...

Restarting is the only fix.

I have heard anecdotes of 'Win Rot', is this 'Apple Rot'?

10.4.11 PPC
1GHz PB, 1GB RAM

[mduell]

Free memory is wasted memory. Don't let memory go free!

Oh, but the paging and related slow down shouldn't be happening.

Does the same happen with Firefox?

[Tee]

Originally Posted by mduell 

Does the same happen with Firefox?

Yes, it does.

[P]

Activity Monitor should force you to read a manual before it shows the memory statistics...

OS X, and any other modern file system, uses a combined disk cache/virtual memory system. Complex algorithms decide what should be kept in RAM, and what should be paged out to disk (that is, written to disk and deleted from RAM). Memory can be classified as one of 4 things: Wired, Active, Inactive and Free. Wired is stuff that cannot be paged out to HD (mostly parts of the kernel). Active is stuff that is currently in use - it can be paged out, but you'd really rather not. Inactive is stuff that is not in active use and can be paged out whenever required, and Free is just that - free, empty, not in use. Free memory can be used directly if required.

When you boot up the machine fresh, take a look at the amount of memory in the 4 categories. Write those 4 values down. Work at the computer for a day and then close apps back down to where you started. Take a look at the stats again. Wired and Active should be the same as they were before, but Inactive should be bigger and Free down to compensate. THIS IS NORMAL, AND NOT AN INDICATION OF A LEAK. The reason is that paging stuff out takes time, and might be wasted labor. If that data will be used again soon, it will just have to be paged in again. This means that the system will leave it in memory but mark it Inactive it can be paged out and cleared at any time. There is nothing to lose by doing that, and much to gain if the stuff you need is already in RAM.

If you want to know if you need more RAM, take a look at the amount of Free + Inactive. If that value is low, you need more RAM. If the amount of Inactive memory grows, all is usually fine. If the amount of Free is very low, but there is lots of Inactive, then something is wrong in the paging mechanism. If both Free and Inactive are low, you either have a leak or you need more RAM.

Long answer, but here's the gist: Please tell us the complete statistics, not just the Free memory, and we'll see if we can help you.

[mduell]

P, take a look at his third paragraph again... "massive page outs and system slow downs/pinwheels/disk churning"

[P]

I saw that, but I'd still like to know the amount of Inactive memory. It should be zero or close enough if he's really running out memory. On late 10.4s, I've seen situations where Inactive stays high but Free drops to nothing - it seems there is something odd in the paging mechanism on occasion. In that case, you get emergency pageouts when the amount of Free memory really runs out, making it look like you're completely out of RAM.