2.6 GHz worse battery life than 2.3 GHz?

[StuLax18]

When conservation of energy ceases and TDP stops being a good marker as to the overall power consumption of a CPU when compared to other CPUs of a similar architecture?

I'm not sure if that's a question or a statement.

But yes, you are correct it can be a good way to compare.

 

[terraphantm]

Intel, like any modern chip manufacturer, Bins their chips, the low leakage chips are sold as the high end models. This means that the 2.6GHz chip may well draw LESS VOLTAGE at the same frequencies than the 2.3GHz chip.

If you remember back to high school physics, and electrical power:

P = VI

You don't pull power, you pull current, you generate power through the flow of current at a given voltage.

Therefore it is likely that the 2.6GHz draws less voltage and therefore has to dissipate less power than the 2.3GHz CPU. However it is clocked nominally higher and the higher clock speed means it draws more voltage. Ultimately, in terms of aggregate sample sizes I am quite sure that the 2.6GHz draws no more power to perform a given workload than the 2.3GHz model.

In more real terms think of the 2.6GHz as having a voltage of 0.9V and the 2.3GHz as having a voltage of 1.0V. The 2.6GHz is about 10% faster both in terms of base speed and turbo speed; one could reasonably assume the current draw is ~10% higher. Let's say that the 2.6GHz draws 45A and the 2.3GHz draws 40A. From the aforementioned equation one can see that the overall power is similar and since a CPU is not a mechanical part for all intents and purposes all power is dissipated in the form of heat thus arriving at the 45W TDP of the quad core chips.

SSD's have minimal power draw (<10W) and since the MBP has a 95W battery in it, it is reasonable to assume that the difference between a Macbook with no drive at all and a very power hungry SSD is ~10% at the highest. The Samsung 830 draws about 5W peak (512GB model).

You also have to consider that sometimes the demand for a low-end SKU is higher than the number of chips that need to be binned that low. So you can end up getting some chips that can be capable of stably doing >3GHz sold as a 2.3 part, and these very well can end up running at a lower-than-typical voltage.

 

[macbook123]

You also have to consider that sometimes the demand for a low-end SKU is higher than the number of chips that need to be binned that low. So you can end up getting some chips that can be capable of stably doing >3GHz sold as a 2.3 part, and these very well can end up running at a lower-than-typical voltage.

Are there safe software tools for limiting 2.6 GHz processors to 2.3 GHz during times where one needs better battery life?

 

[Pagga]

i'd really be interested to see if other 2.3'ers can get a 9+ hour battery life doing light tasks.

I´m consistently getting more than 8 hours with my 2.3 Ghz. I have turned off bluetooth and only use the integrated graphics card (app: gfxcardstatus). I have screen brightness at full or one below (keyboard illumination is off). I got 6.5 hours the first few days, then 7.5 h and now 8-8.5 h. My battery has 7 load cycles so far. Not too shabby I think.

 

[NMF]

Are there safe software tools for limiting 2.6 GHz processors to 2.3 GHz during times where one needs better battery life?

Nope. Impossible.

 

[ekovalsky]

I don't believe there is any significant difference between the 2.3 & 2.6 GHz. I put my rMBP (2.6/16/512) at about 25% brightness, turned off keyboard backlight and bluetooth, have been using Safari for about 15 minutes on WiFi, and it still shows 100% battery with 10:55 remaining.

Sure at load the 2.6 will use a tiny bit more power but it also will complete tasks faster, so it will drop to an idle state quicker. At idle - which is where the CPU will mostly be when surfing on WiFi - both probably draw essentially the same amount of power. Efficiency generally drops as clock speed increases but this only really starts makes a significant difference when attempting major overclocks, then things get very inefficient very quickly. At factory approved CPU speeds, even with Turbo, any difference will be negligible in terms of battery life. The difference in the 2.3 and 2.6Ghz i7 is probably just the multiplier selected by Intel; the silicon itself is likely identical. The 2.7Ghz is different because it has extra cache, and that could adversely affect power consumption independent of clock frequency.

I am fairly certain there is considerable underclocking potential in the rMBP, particularly for the 2.3GHz model. Are there any utilities that facilitate this under Lion or Mountain Lion ? I used RMClock in my Dell XPS Studio 16 which considerably improved battery run time and also kept the fan noise at a minimum. Heat and noise are not an issue with the rMBP thankfully, but more battery run time is always welcome.

 

[phyrexia]

I'm not sure if that's a question or a statement.

But yes, you are correct it can be a good way to compare.

Oh, I misread your question as "When will..." but I'm glad you still get the idea despite my lack of coherence

 

[TickleMeElmo]

You also have to consider that sometimes the demand for a low-end SKU is higher than the number of chips that need to be binned that low. So you can end up getting some chips that can be capable of stably doing >3GHz sold as a 2.3 part, and these very well can end up running at a lower-than-typical voltage.

Yes but one would assume that they put they better chips into the 2.6GHz pile first before the 2.3GHz pile.

 

[ZacT94]

This intellectual debate is most annoying. If you know something to be true why try to convince someone else? You are not getting paid for this so let them stay uninformed and ignorant so that you may take advantage of them in the future.

Finally someone who is talking sense.

 

[archurban]

it doesn't make any difference between 2.3 and 2.6. they all use Turbo boost technology when it is demanded. saving battery life is not really deal for both. in addition, the number 7 hours from 9 hours is not accurate. it's always changed. when you use internet, download something, use few more apps at the same time, it dramatically goes down to less than 4:30 hours. my chronos 7 shows me 8:20 something all the time if I don't do anything. it doesn't show real battery life.

 

[Benlehot]

I have a 2.6/16gb/512gb on order.

Should I cancel it and go for the base model with 16gb?

I don't understand how it's really possible that the base model could get a 1 hour better battery life.

 

[sireShonBohn]

I have a 2.6/16gb/512gb on order.

Should I cancel it and go for the base model with 16gb?

I don't understand how it's really possible that the base model could get a 1 hour better battery life.

Engadget did the test, ask yourself how much you trust Engadget...

 

[Queen6]

I have a 2.6/16gb/512gb on order.

Should I cancel it and go for the base model with 16gb?

I don't understand how it's really possible that the base model could get a 1 hour better battery life.

Well all I can say id you are paying a premium for another 256 storage and no realistic increase in performance. If you absolutely need the 512 so be it if not save you $$$, as for 16GB RAM if you are burning though more than 8Gb now you need it, if you are nowhere close, once again save your money, 8Gb is plenty for heavy use. OS X is designed to page this is a non issue, it`s only a problem if the Page Out`s are excessive, and even this is now lessened due to fast SSD`s

Battery life is still very subjective, however it`s common sense the more you have to power, the greater the consumption, so the base machine should return longer run times, the question is how much longer?

 

[Panini]

Here's what I think:

The only reason the 2.6 will be slower than 2.3 is if it is actually using more cycles. If it is doing work that can be done on a 1.8 ghz processor, it will last longer than by doing work that should be done on a 2.5 ghz processor.

If it is lasting less, then it is actually using those extra cycles for something - perhaps saved time? Less lag?

Shouldn't the macbook air with it's 1.8 processor get 12+ hours according to this?

 

[mdapple]

Here's what I think:

The only reason the 2.6 will be slower than 2.3 is if it is actually using more cycles. If it is doing work that can be done on a 1.8 ghz processor, it will last longer than by doing work that should be done on a 2.5 ghz processor.

If it is lasting less, then it is actually using those extra cycles for something - perhaps saved time? Less lag?

Shouldn't the macbook air with it's 1.8 processor get 12+ hours according to this?

the macbook air WOULD get 12+ hours if it had the same size battery as the rmbp ; )

 

[Abhorred]

You guys didn't figure this out, already?

It's simple: The 2.6 model is more expensive, meaning more professional, and therefore needs more electricity to drive its display than a similar display with lower business value, such as what comes on the amateur 2.3 model. You have to pay for the best to get the best, people. QED.

There, I've contributed my knowledge to this thread. Carry on.

 

[terraphantm]

Yes but one would assume that they put they better chips into the 2.6GHz pile first before the 2.3GHz pile.

Yes, but you also have to take into account that the yields and demand will not always be constant. Let's say in week A, Intel had an unusually strong batch of processors - almost all of them would qualify to be binned as the top-end part. But their orders are such that they have to sell some of them as the budget model. Then the next week, they had a slightly week batch, but they can still safely be binned at 2.6.

In that scenario, you can end up with a 2.3 that's a factory freak, and a 2.6 that's "merely adequate"

----------

Are there safe software tools for limiting 2.6 GHz processors to 2.3 GHz during times where one needs better battery life?

Hmm... if there are any overclocking tools for the mac, they should be able to do it.

 

[mdapple]

You guys didn't figure this out, already?

It's simple: The 2.6 model is more expensive, meaning more professional, and therefore needs more electricity to drive its display than a similar display with lower business value, such as what comes on the amateur 2.3 model. You have to pay for the best to get the best, people. QED.

There, I've contributed my knowledge to this thread. Carry on.

im just going to pretend i didn't read that slosh of sarcasm haha

 

[pandamonia]

Serously? Everyone here is so damn negative that I failed by stating a fact???

GHz has NOTHING to do with speed.....how many pulsing cycles of electricity the CPU can produce. This is how we now have low energy consumption cpu clocks that are MUCH more powerful than they used to be. They can utilize those cycles better and perform more flops per cycle. Less GHz does NOT equal slower speeds....



But of course, the genius masses here are ALWAYS right.

How awesome is it to be 15 and SOOOO smart?

When i come to this forum i really want to smash some peoples head off a wall. Since its the internet i cannot pummel you so i end up having to insult you since physical violence isnt possible. This explains why i end up banned so often.

People like you and the comments you come out with are the exact reason i feel like this.

You have absolutely no idea what your talking about. You should really read and learn before opening your gob.

In a single architectural design of a CPU, less GHZ = LESS SPEED FFS!!!!!

It is possible that a previous design with more GHZ can be slower then a new design with less GHZ but the difference would need to be significant and thus you cant compare GHZ from 2010 to GHZ from 2012.

 

[ivoruest]

Casuality doesn't always imply causality.

 

[Woodcrest64]

I ordered the 2.3Ghz rMBP because of the better battery life and mainly because I couldn't justify spending $600 more. All my pictures and videos are stored on external drives and the difference between 2.3 and 2.6ghz for day to day tasks and some light video editing is negligible to me. I do know its going to be much faster than my Core 2 Duo notebook

 

[asdad123]

I have the 2.6ghz version, and my battery life is great. The longest Ive used it on battery was about 4 hours browsing and I still had 60% left.

 

[Camwin]

I didn't know, so many people knew how to copy and paste from Wikipedia.

 

[Slivortal]

I didn't know, so many people knew how to copy and paste from Wikipedia.

At least people are trying to learn (to some extent), rather than simply being cynical.

But it's true that people need to start looking at the sources CITED in the Wikipedia articles than just taking them at face value. Then MacRumors would become a great educator.

 

[tivoboy]

undecided

Any other reports or tests of the battery life out there?

I'm leaning toward the 2.3 model and getting 16GB of RAM instead of the bigger one. I could buy the higher end model even with the 16GB upgrade, but don't really think I need the 2.6 for most things and while I would love to have 512GB SSD resident, I am certainly able to manage my current 256GB MBP with external storage for movies, large photo libraries and music. The files I use are nothing large, lots of documents and ppts, and a couple of virtual machines. I think the 16GB RAM would go a long way to help out there.

But, I would really like to know if there is a 1-1.5 hour battery life difference. I know it doesn't really make too much technical sense.