[Macworld.com]

Ever had the need to drive your CPUs to 100-percent utilization? Probably not, but in case you ever do, here's one way to do it. [more]

[Nobody]

Why not boot in single user mode? That sends the fans to top speed AFAIK!

[griffman]

Sometimes you want to be able to do other things as well /forums/ubbthreads/images/graemlins/smile.gif.
-rob.

[Gravitas]

Neat article....i just tried it using a iBook G4 at 1.42 GHz and it returned 1662976 lines in .564 seconds resulting in 2,948,539 lines per second. How could be more than twice as fast as your PowerBook G4 running at 1.25? (about 1.3 million lines) I wouldn't think there would be that big of a jump?

[megagram]

Why not just type the command "yes" and not send it to /dev/null. On a multi-processor system, this will drive CPU usage to 100% on both processors. The yes command will display tons of y's causing Terminal to consume tons of processor time displaying these lines. I'm not sure what happens when we get into more than 2 cores or processors. But since terminal is a multi-threaded, multi-processor aware application, it's usage won't be capped to just 100%. On my machine, it used roughly 150% and yes used roughly 50% maxing out both my processors. This will save time and require less open windows.

[elCapiton]

Of course outputting it to a text file might not use 100% CPU because then you're I/O bound by the hard drive speed and not the CPU speed. Good tip though to drain your recalled Powerbook battery before sending it back to Apple.
When I drained my dad's Powerbook with RC5, the CPU was pegged at 100% for a full 50 mins or so from a full charge before it died. Yes it only lasted 50 mins at 100% CPU usage.

[ampm99]

Ok I may be slow but the reason to max the cpu at 100percent is to diagnose any problems that may occur that don't show up at other times? Am I missing something?

[jhmaughan]

Well, at least in this case he just wanted to demonstrate the fan was bad, like maybe a bearing issue. So it required he crank up the CPU to get the fan running to demonstrate the problem.

[jhmaughan]

So you know how they've been touting the quality of Intel chips and how they run cooler? Well, i think that fact, plus apple design, is pretty impressive. I ran the four instances, drove the processors up to full blast, and it took about two minutes for the CPUs to go from their idle temperature of 40 degrees C to 55 degrees C, and when i cancelled all the instances, the temperatures dropped back down to 45 in about 6 seconds and down to 40 about 10 seconds later. The whole time, i didn't hear the fans crank beyond what they usually are. So i thought that was cool. i wonder what it will take to get them up to full speed /forums/ubbthreads/images/graemlins/smile.gif Leaving that running for an hour?

[kyle988]

So they gave you a new MacBookPro just because the fan was faulty? I would have thought they would have just replaced the fan

[maremare]

A much easier way to do this is to run some games, like PopCap's Bejeweled and many applications made in Macromedia Director. Instant 100% processor gratification.

[griffman]

From my experience, that's not true on the Intel boxes, especially across multiple cores. It's tough to find things that really peg both (or all four) CPU cores...that's not to say it's not possible, but even some of the more intense games will vary the load on the CPU depending on the scene being rendered.
-rob.

[AppleTango]

I don't get it. If you stress the processors, the fans are supposed to try to keep them cool. So what? Max out the processor and the fan will max out. What am I missing? Why did he get a new computer? Sorry, I am new to this..

[griffman]

Because when the fan was running, it sounded much like someone had poured a bunch of wet cement into the fan casing, and the fan was churning through it with a grinding, squeaking, terribly loud noise.
That's why I got a new computer /forums/ubbthreads/images/graemlins/smile.gif
-rob.