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i5 vs i7 - battery life differences?

L

.Logan

macrumors regular
Original poster
Aug 7, 2010
110
42
Calgary, AB
Hello,

I have an older Macbook pro, upgrading to a 13" rMBP. Leaving everything standard, except I think I want to get the i7. I really like a snappy machine, don't like to wait, etc. and I feel I would get a noticeable boost with i7.

However, battery life is also important. How much more battery power does the i7 take over the i5? Anyone have lived experience with i7, is it normal, or do you feel battery drains quicker?
 
I have an MBP-13 (Mid 2012) with a Core-i7 processor and typically get 6-7 hours of medium usage (see below for my definition of usage levels). When I do heavy usage, the battery drops to about 4 to 5 hours. I've never owned a Core-i5 laptop but my thoughts are that it would get the same results. The only differences I've found online between the i5 and i7 is hyper threading and hardware virtualization support.

My Light Usage Scenario
  • WiFi Off
  • Microsoft Word / Excel
  • Medium screen brightness
  • No music / video playback
  • Average battery charge yields around 9 hours

My Medium Usage Scenario
  • WiFi On
  • Streaming music from Pandora
  • Medium screen brightness
  • XCode / Xamarin Studio
  • Microsoft Word / Excel
  • Average battery charge yields around 7 hours depending on how many compilations I perform during a session and device emulators I run. :p

My Heavy Usage Scenario
  • WiFi On
  • Medium screen brightness
  • Streaming music from Pandora
  • XCode / Xamarin Studio
  • vmWare Fusion 6 running Windows 8 and Visual Studio (Note: I allocated only a single core with vmWare Fusion for the Windows 8 VM. That keeps the Mac happy overall and gets me better mileage battery wise. Your mileage may vary.)
  • Microsoft Word / Excel
  • Average battery charge yields around 5 to 6 hours
 
.Logan said:
Hello,

I have an older Macbook pro, upgrading to a 13" rMBP. Leaving everything standard, except I think I want to get the i7. I really like a snappy machine, don't like to wait, etc. and I feel I would get a noticeable boost with i7.

However, battery life is also important. How much more battery power does the i7 take over the i5? Anyone have lived experience with i7, is it normal, or do you feel battery drains quicker?
Click to expand...

The power draw is nearly identical.

What do you actually use your computer for? 95% of people aren't limited by their processor, but something else, such as RAM.
 
Sure! I think I'm becoming sucked into the "more is better" mentality, and I've been unhappy with the speed of my 2011 macbook and just want something so much faster. I don't currently have a SSD, so that alone should make a difference right?

I'm a science student, so: I do a lot of web browsing, microsoft office, listen to music, watch movies, and that's about it. I just like to multi-task and have multiple applications open which I find a struggle right now on my current 13" MBP.

Would the new base model be enough for me?
 
.Logan said:
Sure! I think I'm becoming sucked into the "more is better" mentality, and I've been unhappy with the speed of my 2011 macbook and just want something so much faster. I don't currently have a SSD, so that alone should make a difference right?

I'm a science student, so: I do a lot of web browsing, microsoft office, listen to music, watch movies, and that's about it. I just like to multi-task and have multiple applications open which I find a struggle right now on my current 13" MBP.

Would the new base model be enough for me?
Click to expand...

None of those tasks would even remotely benefit from a more powerful processor.

The bottle neck on your current computer is more than likely the hard drive or the RAM.

I don't know how familiar you are with computers but I can make an analogy of sorts.

Think of RAM as a desk in front of a very fast clerk (the processor). The bigger the desk (the more RAM) the more work you can put in front of the clerk for him to access quickly and process.

If you even run out of desk space (not enough RAM), the clerk puts work in the desk's drawer, which is a much slower operation as he has to open the drawer, put work in there, close it back up, and do the opposite when it comes time to work on it.

If you are lacking RAM, you will see a very steep decrease in overall response from your computer as it is much slower to write and read to a hard drive than to RAM (ram is over 100 times faster).

Since your computer is upgradable, we can help you determine if that is your case.

Next up, there's the upgrade to the SSD. To put things into RAM, the computer has to read it from your hard drive, the faster the hard drive, the faster stuff is put into RAM. That operation happens whenever you boot, open a file, application or launch calculations (be it photo editing, video editing, rendering or whatnot). So a SSD makes the computer feel much "snappier" as things will open faster.

Hope that helps you out, I have a feeling you want to upgrade for upgrading's sake, as your computer is more than capable of dealing with the tasks you described.
 
I do want to upgrade just for the sake of upgrading mostly because my room mate has offered to buy my current laptop for a fair price therefore making upgrading an affordable option when compared to just buying a SSD to upgrade my current laptop.

Thanks for the analogies, that was helpful! So given my current tasks, and adding a SSD, would 8GB RAM be enough or should I actually be looking at 16GB?

Thanks!
 
.Logan said:
I do want to upgrade just for the sake of upgrading mostly because my room mate has offered to buy my current laptop for a fair price therefore making upgrading an affordable option when compared to just buying a SSD to upgrade my current laptop.

Thanks for the analogies, that was helpful! So given my current tasks, and adding a SSD, would 8GB RAM be enough or should I actually be looking at 16GB?

Thanks!
Click to expand...
Impossible to say as I haven't seen a screenshot of your activity monitor showing the RAM tab when you feel your computer is "sluggish".

More RAM is useless if you're not running out of it, so let's see that screenshot shall we?
 
Attached. So "Memory used" is 6.8GB right? So getting close to 8GB?
 

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.Logan said:
Attached. So "Memory used" is 6.8GB right? So getting close to 8GB?
Click to expand...

http://support.apple.com/kb/HT5890?viewlocale=en_US&locale=en_US

Your memory pressure is in the green, your currently used RAM is 3.45GB of App memory and 1.88 of Wired memory, which totals 5.33GB, meaning you have 2.67GB of RAM left.

The "File Cache" is OS X's way to have things opening faster. It'll keep quitted apps in RAM until that RAM is needed for something else, in case you'd want to open that application back up soon.

Things like Office for Mac are quite slow to open on a hard drive. Give it a try. Open Word, and quit it. Then open it back up. It'll open up nearly instantly as it was still in RAM.

I'd say you'd probably fare well with 8GB, but if you feel your needs may grow in the future, the upgrade to 16GB isn't all that expensive for peace of mind.

This is my two cents worth, don't take what I say for granted, you're the one buying a new laptop, so buy what makes sense to you.
 
Thank you for your input, very insightful! I wasn't sure how to best interpret the RAM usage screen.

I notice lot of people on their macs just minimize everything, and leave everything open as opposed to quitting which I like to do. Is that a good idea to/does it matter?
 
.Logan said:
Thank you for your input, very insightful! I wasn't sure how to best interpret the RAM usage screen.

I notice lot of people on their macs just minimize everything, and leave everything open as opposed to quitting which I like to do. Is that a good idea to/does it matter?
Click to expand...
It leave the app in RAM ready to be used again.

I have 16GB of RAM so I usually don't bother quitting apps and often have multiple desktops full of them.

Back when I had my other MBP which my GF now uses, I only had 4GB so I would quit anything not being used.
 
.Logan said:
Hello,

I have an older Macbook pro, upgrading to a 13" rMBP. Leaving everything standard, except I think I want to get the i7. I really like a snappy machine, don't like to wait, etc. and I feel I would get a noticeable boost with i7.

However, battery life is also important. How much more battery power does the i7 take over the i5? Anyone have lived experience with i7, is it normal, or do you feel battery drains quicker?
Click to expand...

I have an i7 13" rMBP. It still lasts as long as an i5 as the TDP is very similar.

But personally speaking, you won't see any performance improvements between the 2.6GHz i5 and 2.8GHz i7, because both only have 2 cores and 4 threads. A quad core i7 on a 15" is a completely different story.

The only reason I have an i7 is because the rMBP was maxed out by my dad and purchased for me. If it was on my own dime, I'd go for a 2.6GHz i5, 16GB RAM and 512GB SSD.
 
i7 on the 13'' doesn't make much sense... but if it makes you happy, go for it

For the RAM, the usual advice is that if you have to ask whether you need 16 GB then you probably don't need it. 8 GB however I think is almost mandatory.

The $1500 model with 8/256 GB is a good solution for most people.
 
yjchua95 said:
But personally speaking, you won't see any performance improvements between the 2.6GHz i5 and 2.8GHz i7, because both only have 2 cores and 4 threads. A quad core i7 on a 15" is a completely different story.
Click to expand...

For his usage, I'd be amazed if he's ever processor bound, therefore even the quad core i7 wouldn't make much difference.
 
yjchua95 said:
He won't be processor bound. I was just comparing the differences between a dual-core processor and a quad-core one.
Click to expand...

Sorry, I wasn't questioning your analysis of the various processors. Just clarifying in the context of this thread, for the OP and those in a similar position, even the quad core is unlikely to yield any return on the further investment.
 
Power usage is a funny thing.

When an application is running it theoretically uses more power on an i7. But as the i7 is faster the processes will finish quicker and the CPU will go back to idle mode quicker.
This means that the CPU uses more power when working but works for shorter periods thus negating the fact that it uses more power.

In the end, under normal usage, an i5 and an i7 will drain your battery at the same rate.

Once you start playing games though either the i5 or the i7 will run at full power which will result in the i7 draining the battery quicker!
 
you need an SSD dude, that is going to make every difference in the world for your casual usage.... slap one in your '11 and it will be like a brand new machine, no doubt about it.

but as for a new machine and battery life, you'd be upgrading to haswell so.... i wouldn't worry about it, is gonna be pretty tight....

i wouldn't doubt i7 would drain your battery considerably quicker if say you were transcoding a movie in handbrake, lol, but nobody is doing that off the brick to begin with... but for your usage it's a complete waste of money.... 16gb of ram is also a waste of money imho unless you think maybe some day down the road you might want to do something a power user would do, or even quasi power user, like maybe virtualizing windows.... i do a couple dozen tabs on my 4gb macbook air and itunes, irc client, instant message client, word processor, etc. and it performs identically with my 16gb retina macbook pro for those type of activities.... cuz that's nothin..... it's not like you're future proofing for the day when surfing some web pages on a newer version of os x will suddenly takes way more ram... ain't gonna happen... the only future proofing you'd be doing is if you actually decide to use your computer in a dramatically different way than you currently do.
 
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Thank you everyone for your replies! It was really helpful in guiding my decision. It's obvious I didn't understand what tasks used processor vs which didn't. I'm pretty good from a software perspective, but hardware has never been a strong suit.

Given an opportunity to upgrade as I have a buyer of my old macbook for a fair price, I ordered the:

13in rMBP- 2.4Ghz i5 - 16GB RAM - 256GB SSD

Very excited to experience a SSD, it sounds like that is where I will notice the most improvement from! I also like the idea of future-proofing my Macbook with the increased RAM. I do a bit of freelance web development and that may increase in the future, but no I would never get into video/audio editing and I don't see myself using VMWare. Mostly school/office related applications, web browsing, and I don't want any limits on multi-tasking or how much I have open. Sounds like this machine will more than meet those needs.
 
.Logan said:
Thank you everyone for your replies! It was really helpful in guiding my decision. It's obvious I didn't understand what tasks used processor vs which didn't. I'm pretty good from a software perspective, but hardware has never been a strong suit.

Given an opportunity to upgrade as I have a buyer of my old macbook for a fair price, I ordered the:

13in rMBP- 2.4Ghz i5 - 16GB RAM - 256GB SSD

Very excited to experience a SSD, it sounds like that is where I will notice the most improvement from! I also like the idea of future-proofing my Macbook with the increased RAM. I do a bit of freelance web development and that may increase in the future, but no I would never get into video/audio editing and I don't see myself using VMWare. Mostly school/office related applications, web browsing, and I don't want any limits on multi-tasking or how much I have open. Sounds like this machine will more than meet those needs.
Click to expand...

I can confirm that. I have a late 2008 MacBook unibody core2duo. Last year i wnted to upgrade and was told that the bottleneck isn't the processor but the HDD speed.

RAM upgrade from 2 to 4 GB was noticable. But replacing the combo drive with an SSD more than doubled the overall speed. Now having 256 GB SSD + 1TB HDD.

Again doubling RAM to 8GB didn't bring any noticable improvement. I guess that's the processor limit now.
 
really does depend on your usage.

I have an i5 with 8G ram ... I need VMware to run windows 7 related to work.
8 G isn't enough for the host and guest operating systems together. Checking my memory usage from time to time I;m using a fair bit of swap space.

performance wise, the 2.6Ghz cpu has been great.

256G flash drive is tight ... I just have to cleanup periodically.
 
I have changed all my Windows computers to SSD and it made a world of difference and the reason I bought my new MacBook Pro with one also.
 
In 2014, processor upgrades on laptops are pretty much pointless. Unless you are professional that is constantly on time sensitive project and literally EVERY second saved counts, there is no reason to spend the money to processor upgrades. SSD and RAM will impact and bottleneck performance long before the CPU for at least 80-90% of people.

In contrast to desktops, where is the difference between an i5 vs i7 vs Xeon is more than just clock speed.
 
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