- Feb 13, 2007
I was using my sr-mbp on the battery today, and when i used the expose and or the dashboard, i noticed that it didnt run as smoothly as it does when its plugged into the wall. Is this normal?
Better performance makes it less likely for the CPU and GPU to scale back clock speed to preserve battery life. Better battery life makes it more likely for the CPU and GPU to scale back clock speed to preserve battery life. Normal is a balance between them.There are three settings - Better Battery Life, Normal, Better Performance. What the real world difference is I don't know.
Hmm, you may be right but still, if its unplugged with full battery or low battery, it still seems to run a little less smoothly for the expose/dashboard features. However, i tested running World of Warcraft while purely on battery power and it seems as if it ran just as well as it does on AC power. So i think the cores maybe slow down for general os use, but when needed (HD quicktime file, or games) maybe thats when it runs back to normal? Just a hunch maybe. Any thoughts?The Power Management settings that you refer to do not affect processor throttling on Intel processors; that is an artifact left over from the age of PPC Macs. The settings you refer to (Better Performance, Normal, Better Battery Life) now only adjust the time until screen sleep or computer sleep that you can adjust to your own custom settings. If they actually did affect processor frequencies, then what does "Custom" equate to in terms of performance? It doesn't make sense.
As far as I know, neither of your cores' operating frequencies are reduced when you switch from AC power to battery power. The Processor control panel that is part of the CHUD Developer tools shows that both cores are operating at 2.40 GHz whether my SR MBP is plugged in or working on battery. The only thing I can think of is that the frequency might be reduced when your battery starts to run low (?), but I haven't tested it myself.
Without any hard proof on either side (I can't prove that it isn't slowing down, but you can't show that it is), I'm tempted to say its just a placebo effect and that your computer either isn't slowing down or is slowing down for some unrelated reason.