Monitoring your Ram and making sure you have enough!
Activity Monitor is a very useful tool in ensuring that the quantity of Ram you have is not what is slowing everything down. With the powerful computers we have today, the two things that can be a huge slowdown is an hard drive without enough free space and not enough Ram. You should always have at least 10% (or 10 GB for smaller hard drives) of free space. Not enough Ram also slows everything down, because the OS will constantly swap data to the hard drive and the hard drive is slow. Here is what Activity Monitors tells you about your Ram:
There are four categories: Free, Wired, Active and Inactive. What is actually being used now is Wired and Active. The sum of Free and Inactive is what is unused. You might want to consider having enough Ram so that you don't have to use the Inactive memory, because Inactive memory often adds a lot of speed. What is stored in Inactive memory is the data of an application that was running previously. That is why it is always faster to load an application the second time. This is exactly what Apple does when presenting their software. They load it once, quit it, and load it again in front of the camera. It looks much snappier the second time because everything is still stored in the Ram. To really understand if you need more Ram, you'll have to look at the "Page outs". Page outs are data that had to be transferred to the hard drive because the OS ran out of Ram. It is normal to have some Page outs if your computer has been running for a while, because the quantity of Page outs is only reseted when you restart. The best way of seeing what is going on is to leave Activity Monitor running and watch it while working. When you have many applications running and you see that it is accumulating a lot of Page outs, it is safe to say that more Ram would probably speed things up a lot!
posted by Frederic Tremblay at
11/11/2007
17 Comments:
How many is a lot of page outs? I have 41,000 and my computer has been on for 4 days. But I also have 2 gigs of RAM and most of the time at least 500 MB of it is inactive.
Great explination of the 4 types of ram. I monitor mine through iStat (both desktop and widget). I've never understood the difference between Active and Wired. Any insight into that?
Hey there is a cool add on called i stat pro for the tool bar at the top that allows you to monitor all actives such as network, cpu and memory from the tool bar
How do you decrease the amount of ram used? My stats definitely does not look very good. No wonder my computer has been really slow lately.
300,000 page outs over 35 days, with 800+ megs of free ram... Good? Bad?
i'm going to have to jump on the wagon here as well. how do we find out the correspondence between page outs/time vs. what is average or what is too much?
my computer has only been on for about 6 hours and i've accumulated 96000 page outs.
(2.16GHz, Core 2 Duo, 15 GB left on 80 GB hard drive, 1 GB RAM)
- anyone have any idea on what "average" should be? or should i just wish myself a happy birthday and buy another gig of RAM and call it a day. :-)
In the Leopard version of Activity Monitor, Page outs are in kilobytes or megabytes. It is much easier to see how much time you lose in terms of megabytes/kilobytes. My last restart was about five hours ago and I have 376 KB. That's nothing because the time lost is the equivalent of the time it takes to copy a 376KB file to your hard drive. It is also much easier to see when you are working with many applications running. Mine is fine right now because I only do regular tasks (although multitasking) with 2 GB. My Page outs really go up when I multitask with Pro Apps. My free ram also goes down to something like 40-50 MB. That is where I would take advantage of 4 or 6 GB.
Interesting comments. In my case, Parallels has a major effect. I ran it for 5 minutes and had no Free (green), reduced Inactive (blue) and stcks of Wired (red). 58000 pageouts in the 5 minutes.
This was after defragging.
Is there a way to make more inactive/free?
Active RAM is currently being used by an application or the operating system. Wired RAM is memory that cannot be cached to the hard drive thus freeing it to Inactive. Inactive RAM is basically RAM that has been used by an app and is cached to the disk and kept in RAM for further use. This is to speed up performance of that app if it is used at a later time. Said inactive RAM is supposed to release for another app if the original app is no longer running. I find it doesn't always do that and effects performance. I have 4 GB on my MacBook Pro and I still run out of free memory all the time. Especially because of Parallels... The only way of releasing inactive RAM that I know of is restarting and and a utility called iFreeMem (http://www.activata.co.uk/products/ifreemem.html). It works like a charm. And as for memory paging, that is typical not something that should cause concern. One would see more paging with less RAM installed. In this situation, having more free hard drive space would help performance as disk caching is easier. Think of it as Virtual Memory from OS 9. More RAM and free hard drive space is desirable, but one has to live with what one has.
I find that I forget that I have several browsers running with many many pages open. Then I also forget that Ive got tons of programs running too.
But luckily when I bought these 2 iMacs, I had the max amount of RAM installed that the things would hold. I realize now that this is the most important thing you can do!
Sometimes things do slow down a bit, and I have to quit some of the programs like the big Adobe ones that I forget and just leave running.
Jane
If you don't want to have Activity Monitor running all the time there is another tool that take up less screen space and can be way more useful.
Geek Tool from http://projects.tynsoe.org/ is really nice. It can display all kinds of useful info on your desktop and takes up far less system resources than Activity Monitor.
I currently use it to display current date and time, uptime, top, and df. I display all this on my secondary monitor so I can see it pretty much all the time.
Getting "top" to display correctly is a bit tricky, but there are some articles out on the web that can help you get "top" displaying with a minimal effort. One such article is: http://www.keynote2keynote.com/?p=119&akst_action=share-this
GeekTool is Leopard compatible and very affordable. Free. :)
To Jamie:
you have success with iFreeMem? i have it on my machine, but I dislike how, through the process of freeing up RAM, it seems to slow down every program i have running...is there something i'm missing?
Re: Aaron
iFreeMem also bogs down my system during memory free-up. That happens because iFreeMem momentarily utilizes all inactive RAM (and free), forcing it to be released from what ever used it and clears the RAM cache. For me, with 4 GB of RAM, that lasts maybe two minutes. The slow down is usual. I find it's worth the inconvenience to free up my RAM.
awesome. thanks for the quick reply!
No sweat!
For Jamie
Thanks for the tip. I'm testing iFeeMem. It seems that Parallels takes up wired RAM and even iFreeMem doesn't have much effect on it.Ah well, that's the price of keeping the PC side. Or, should I say, one of the prices eg the keyboerd is different.
Gnarly. I've been reading this blog for a while and once again, you have proved informative. I've always wondered the difference between free and inactive, just never been bothered to find out for myself.
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