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Why do I have to restart?

G

glib

macrumors member
Original poster
Mar 7, 2006
57
0
Not sure if this belongs here, or in the gaming forum, but I'll start it here first.

After reading up on the WoW threads about getting best performance from my core duo mbp, I think I got it all tweaked up nicely. I was getting a nice 30-40fps outside, and 60ish inside, which was a good balance between quality and performance. But after doing some other things on my computer for a while (torrents, music, surfing, adium etc... the usual) I started up WoW again to find 10-15fps as the average. I tried everything I could think of, then gave up and gave it the old windows-style-restart-fixes-everything fix, which seems to have done it.

So my question is what was slowing my computer down. Since it goes to reason other parts besides wow were running at close to 50% of their full speed, what was causing it? My cpu usage was below 5%, ram was fairly empty, nothing was open.

Ideas?
 
general over time you ram can get messy and fragmented. Also you page files can of grown quite a large and a restart allows it to be dumped. A lot of it could just be the ram is only being used at 5% but the 90+% you where using is just not cleared out yet. You computer says it free but it still being cleared out of the OS and what not. Restart just completely wipes it clean.
 
Is there an app to zap my ram clean then? It couldn't be pagefile fragmentation could it? I remember only having to defrag my pagefile maybe once every few months when I was running linux. I guess that could be a result of having the pagefile on a separate swap partition, whereas osx just does everything in one big partition windows-style (at least I think it does?).
 
glib said:
Is there an app to zap my ram clean then?
...
Click to expand...

Sure is! It's in the Apple menu, and it's labeled "Restart" ;)

The problem is that all code is faulty, none of it is 100% bug free, and even if the code is fine, the third law of thermodynamics will eventually introduce errors.
RAM has to be refreshed several thousand times a second. Combine that with even a very tiny memory leak in just one application, and eventually the system slows down. In addition, you get RAM fragmentation as part of this process (as mentioned by another poster)
The problem with dumping the contents of the RAM and refreshing them is that the operating system is loaded into RAM. Dumping the entire contents would just cause the computer to crash.
Another issue is caching. When the computer has been on for a while and you've opened up a lot of different applications, parts of these applications are stored in RAM or virtual memory even after the application has been closed. This is done by design so that the program will start up faster next time. The system will eventually clean that kind of cached data on it's own, but in the meantime, that memory won't be available to other programs. On the same note, sometimes due to bad programing, and sometimes just due to random errors, parts of programs will be still left in memory after they close.

As for software to clean all this up, I'm not sure about OS X, but there are a few such programs for Windows 9x. But even they only have limited effect, as they can't clean up what's being currently used by the system, and sometimes actually cause system instability if they try.

And in case you're wondering why a reboot fixes the problem: As mentioned above, RAM has be refreshed constantly. RAM is really a series of capacitors that store electricity for a very brief time. When the computer is on, it is constantly refreshing the capacitors that hold a charge. When you reboot the computer, power to RAM is switched off allowing the capacitors to complety drain, thereby thoroughly reseting all memory.
 
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