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Tinman · 11-13-2007, 01:56 PM

Originally Posted by mobilehavoc

Most mobile ARM CPUs use some form of cpu scaling to make the most out of battery life - which is probably what you're seeing. I always thought the supposed Samsung ARM CPU in the iPhone was rated for 600mhz too.

If you think about it, it doesn't make sense to run the CPU at full speed unless there's sufficient load.

Using VT-Term100 or SSH you can run 'top' on your iPhone which gives you a live sys monitor (auto refresh). Using SSH you can leave this open and then run stuff on the iPhone. You rarely see CPU % go higher than 60% for more than a second. This leads to believe 400mhz is the battery saving frequency and it only runs at 600mhz when needed.

I think the 600 MHz rumors were just that. I have found zero confirmation that the iPhone ever runs at that speed.

Moreover, I found this:
"Now let’s take a look at the CPU speed. Again, sysctl() is our friend, this time using CTL_HW with HW_CPU_FREQ and HW_BUS_FREQ. The results of our test show that the CPU is specified at 400 Mhz with a bus frequency of 100 Mhz.

There have been various hardware reports that place the ARM chip’s frequency above 600 Mhz. Maybe sysctl() is lying to us, or maybe the CPU is clocked down to give improved battery life. Only Apple knows that for sure."

http://furbo.org/2007/08/21/what-the...dont-tell-you/

So it seems the iPhone has indeed been sped up.

--
Mike

11-13-2007, 01:56 PM	#7 (permalink)
Tinman Join Date: Jul 2007 Location: Aridzona Posts: 3,004 Thanks: 45 Thanked 117 Times in 73 Posts	Originally Posted by mobilehavoc Most mobile ARM CPUs use some form of cpu scaling to make the most out of battery life - which is probably what you're seeing. I always thought the supposed Samsung ARM CPU in the iPhone was rated for 600mhz too. If you think about it, it doesn't make sense to run the CPU at full speed unless there's sufficient load. Using VT-Term100 or SSH you can run 'top' on your iPhone which gives you a live sys monitor (auto refresh). Using SSH you can leave this open and then run stuff on the iPhone. You rarely see CPU % go higher than 60% for more than a second. This leads to believe 400mhz is the battery saving frequency and it only runs at 600mhz when needed. I think the 600 MHz rumors were just that. I have found zero confirmation that the iPhone ever runs at that speed. Moreover, I found this: "Now let’s take a look at the CPU speed. Again, sysctl() is our friend, this time using CTL_HW with HW_CPU_FREQ and HW_BUS_FREQ. The results of our test show that the CPU is specified at 400 Mhz with a bus frequency of 100 Mhz. There have been various hardware reports that place the ARM chip’s frequency above 600 Mhz. Maybe sysctl() is lying to us, or maybe the CPU is clocked down to give improved battery life. Only Apple knows that for sure." http://furbo.org/2007/08/21/what-the...dont-tell-you/ So it seems the iPhone has indeed been sped up. -- Mike __________________ "When this sign is under water, this road is impassable. -posted on a Tennessee highway