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Level 1

10 points

SMC Firmware Clamps Processor Speed?

Just installed the SMC firmware update.
Cooler: Running CoreDuoTemp v0.51, I couldn't push the temp past 70, whereas I reached mid 80's before.
But SLOWER: I can't (according to the CoreDuoTemp program) push it past 1000Mhz, the chip's minimum. It used to idle at 1500, and push to 1830. To boot, things like iTunes visualizer are noticeably slower.

So...well, this would obviously explain the heat difference. It's nice having a cooler operating temp, but are we really capped at 1.0 Ghz to get it? Can anyone else confirm?

BTW, is there any other program that will give a readout of current clock speed?

1.83 MacbookPro

Posted on May 16, 2006 8:27 PM

94 replies

May 18, 2006 7:35 AM in response to Mardacious

Well, now I am confused.

Is what people are saying is that the processor speed is clamped down when the computer is running on battery power? Is that regardless of the power usage setting?

Man...I don't do ANY updates until I have read the forums for a week! There are probably 7 things in the software update that I haven't done yet.

May 18, 2006 7:50 AM in response to Mitch Towne1

The top speed is not clamped (unless CPU internal temperature exceeds the maximum), but the bottom (when demand is low) is lowered, leading to less battery consumption from idling or intermittently used machines.

Stop second-guessing Apple’s engineers. They know more than we do.

RRS

Rich88

Level 1

4 points

May 18, 2006 9:46 AM in response to hiaw

It's a pity cause leaving the battery plugged in on
AC is bad news for battery life....

Wha is the basis for this claim?

May 18, 2006 10:14 AM in response to Rich88

the basis is bollocks! :P

when the light turns green the bettery is charged full and bypassed

Mac MD

Level 1

40 points

May 18, 2006 11:12 AM in response to Mardacious

Installed the "SMC Firmware Update" and have noted a significant drop in operating temp when pushing the processors. Temp has dropped from 60° to 65° C to 50° to 55° C. I have "CoreDuoTemp" on the desktop and my CPU frequencies seem to run from 1667 MHz with Safari and minimal activity to 2167 MHz when I push the CPU; iTunes with Visualizer on "Large", iPhoto opening and selecting 1,000 photos, Safari downloading file, all running at the same time. As I stated, I have yet to see the CPU drop below 1667 MHz and as I gradually "stress" the CPUs, the CPU frequencies increase and decrease based on load as expected.

MacBook Pro 2.16 GHz 2 Gig RAM 7200 RPM HD Mac OS X (10.4.6) ADC Select Member

May 18, 2006 11:19 AM in response to Rich88

He is right. A lithium-ion battery should be used regularly to ensure the battery can extend to it's full manufacturer's implied life-span. Leaving the battery always plugged in will in fact decrease the length of time the battery will operate because the battery is remaining dormant and not being cycled. Apple states on their battery page, "Lithium-ion batteries need to be used for maximum performance. If you don’t use your device often, be sure to complete a charge cycle at least once per month." On the Notebooks page, they also state "Apple does not recommend leaving your portable plugged in all the time...A properly maintained Apple notebook battery is designed to retain up to 80% of its original capacity after 300 full charge and discharge cycles."

If you plan on leaving the system plugged in all the time, then you should as suggested, discharge the battery once a month.

Mardacious Author

Level 1

10 points

May 18, 2006 12:08 PM in response to Mardacious

I'd be the last to doubt Apple's engineers--it's the damage control/PR people I'm afraid of. 🙂

Atim from Hong Kong seems to have spotted the issue--running on AC power w/o battery (as I'm doing, as my battery was a dud) will throttle the chip down. No problem there. I'm still waiting on a replacement battery for my dead'un to confirm (just got off the phone w/AppleCare, they are backordered on MPB batteries--seems like there was definitely a bad batch). So it seems the SMC Firmware update, among other things, drops the "floor" for the chip to a lower frequency to run cooler when you don't need the extra horsepower. Makes sense to me.

PS: As for the balance of the case heat, I recently bought and can vouch for the Cooler Master "Notepal" riser. Cools the case a bit, and saves the finish on my desk. I won't link to it here, but it's a pretty good li'l tool.

Thanks for everyone's help...

May 18, 2006 1:01 PM in response to Mardacious

I really apologize if I sound dense here...but do you mean running the MacBook Pro plugged in with the battery physically out of the machine?

Mardacious Author

Level 1

10 points

May 18, 2006 2:52 PM in response to Mitch Towne1

Sort of: There was apparently a string of faulty batteries (the subject of the "silent recall" reported a few weeks ago) that immediately lost the ability to hold any charge whatsoever--becoming a $129 paperweight. In my case, the battery was so "dead" (dropping dramatically from a 3 hour charge-capacity the day before) that the system simply didn't recognize there was any battery there at all--the funcitonal equivalent of running on AC power without the battery in its bay. So, long story even longer, the answer is yes. And there shouldn't be any other case in which running on AC w/o a battery in the bay would be typical or advised, as far as I know.

Morn

Level 1

30 points

May 19, 2006 12:04 AM in response to Rich88

He's quite right, the basis for the clam is heat reduces the life span of a lithium ion battery. And this MBP's can get quite warm. So leaving a battery in a MBP can make it not last as long, although I don't think I'd bother to take it out just to increase it's life span slightly too inconvenient.

veshman

Level 1

0 points

May 19, 2006 7:02 PM in response to Mac J

I used the command "yes > /dev/null" as done by a previous poster and got the following results:

Before the update:

Temp: 70 - 80 Celsius
CPU Usage: 100%
Processor Speed: 2000Mhz

After the update:

Temp: 39 - 44 Celsius
CPU usage: 100%
Processor Speed: 2000Mhz

A significant difference in operating temperature as you can see. The laptop I am using was purchased about 5/02/06. My brother's laptop, which is also a 15" macbook pro 2Ghz, was purchased 04/08/06 after the update runs at about 80 Celsius with the update installed (don't have previous numbers for him).

Bhavesh
veshman.com

migs

Level 1

10 points

May 19, 2006 9:00 PM in response to veshman

veshman, are you sure that you are measuring CPU temp and not HD temp when running the cpu's full at 100%?

May 19, 2006 9:08 PM in response to hiaw

I've used a PB as a desktop, permanently plugged in (except for occasional travel) for nearly three years with no noticeable degradation of battery capacity. It's a great system -- a built-in UPS -- and the biggest downside is having to buy a new battery now and then -- something that has yet to happen to me and that I consider much more acceptable than the consequences of a sudden power loss (especially with MagSafe). My MBP is 6 mo. old, has seen six charge cycles and still has >95% of its full battery capacity. I wouldn't hesitate to use the MBP this way.

veshman

Level 1

0 points

May 20, 2006 12:32 PM in response to migs

migs,

I think so..i'm reporting what I am getting from CoreDuoTemp.

Interestingly, today i am using it without taxing the processors, and it's reporting 60 Celsius

after turning taxing the processors for a while the temp went up to 63 Celsius

dapo

Level 1

8 points

May 20, 2006 9:53 PM in response to Mardacious

I have the exact same problem. Handbrake is horribly slow now. It went from 24fps down to ~10-11fps. I have not seen the speed hit 2000 Mhz since I installed the update, even at idle.
My new MacBook Pro is now slower than my powerbook G4.

SMC Firmware Clamps Processor Speed?