The MacBook Pro Review (13 & 15-inch): 2011 Brings Sandy Bridge
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on March 10, 2011 4:17 PM EST- Posted in
- Laptops
- Mac
- Apple
- Intel
- MacBook Pro
- Sandy Bridge
Battery Life
With the potential for higher power draw, battery life on these new systems has the chance to be really, really bad. In reality it breaks down like this: light usage cases are equal if not better than last year's model. Apple makes up for the higher core count of the 15-inch MBP by capping turbo speeds and being very good about allowing the CPU to go into deep sleep states under OS X. On top of that, Sandy Bridge is a very efficient microarchitecture that manages to get work done quicker than Arrandale and get to sleep faster.
Heavy usage cases however can easily be worse than last year's model, specifically with the 15 and 17-inch systems. The new 13 is a mixed bag. Core 2 was a pretty low power architecture, beating its battery life will be difficult. The only scenario our battery life tests don't duplicate is one where workload scales with performance. Right now all of our tests are fixed workloads: web pages may render quicker, but you'll still be idle for the same amount of time regardless of system. Video frames may decode quicker, but they'll still play back at the same 24 fps. If you use the additional performance of these systems to do more then you'll likely see even worse battery life (see the power numbers on the previous page).
Light Web Browsing
Here we're simply listing to MP3s in iTunes on repeat while browsing through a series of webpages with no flash on them. Each page forwards on to the next in the series after 20 seconds.
The display is kept at 50% brightness, all screen savers are disabled, but the hard drive is allowed to go to sleep if there's no disk activity. The wireless connection is enabled and connected to a local access point less than 20 feet away. This test represents the longest battery life you can achieve on the platform while doing minimal work. The results here are comparable to what you'd see typing a document in TextEdit or reading documents.
For the 15-inch model battery life has doubled since 2008. Even compared to last year's model Apple has actually improved idle/light usage battery life by 8%. With 9 hours of battery life I can confirm that if you're just using the 15-inch MBP as a glorified typewriter this is what you'll see. It's a great combination of a system that has performance on tap but the battery life to last you if you just need to do some writing.
The 13-inch MacBook Pro actually takes a step back compared to last year's model but it's still the Mac with the 3rd longest battery life.
Boot Camp Battery Life
Under Windows 7 there's no option to use the iGPU, the 15 and 17-inch MacBook Pros default to their dGPU. As we already showed, simply enabling the dGPU hurts battery life. What about the move to Windows 7 on top of that? To find out I ran our light web browsing battery life test under Windows 7. I subbed in IE8 and Windows Media Player for Safari and iTunes and otherwise ran with similar settings as our Mac test:
Compared to OS X with the dGPU enabled, Windows 7 delivers 20% lower battery life. The bigger penalty however is the forced dGPU usage under Windows. If you're planning on using the new 15-inch MBP as a Windows notebook, don't expect to get anywhere near the battery life that is promised under OS X.
Flash Web Browsing
The test here has three Safari windows open, each browsing a set of web pages with between 1—4 animated flash ads per page, at the same time. Each page forwards onto the next after about 20 seconds.
As always, the display is set to 50% brightness, audio at two bars, screensaver disabled and the hard drive is allowed to go to sleep if idle. The wireless connection is enabled and connected to a local access point less than 20 feet away.
Turn Flash on and up the intensity of the workload and the numbers get a lot more reasonable. The new 15-inch MacBook Pro leads the pack with 7 hours of battery life. You'll note that this is exactly what Apple promises on its website. At 7 hours this is also a 20% improvement over last year's model. Other than OS/optimization differences the only explanation I have here is that Sandy Bridge provides a sufficient enough increase in CPU performance to render a page and flash ads get to sleep quicker compared to Arrandale. Another contributing factor is the new 32nm iGPU which is active full-time under Safari. The GPU alone is probably a bit more efficient at rendering flash than last year's GeForce GT 330M.
The 13-inch model actually equals its predecessor. I suspect the Core 2 Duo is still a lower power CPU under a moderate load.
XviD Video Playback
I ripped The Dark Knight to XviD and played it back continuously in QuickTime X with Perian installed. For this test the display was set to full brightess and audio was set at two bars below maximum. Once more the hard drive was allowed to go to sleep if it was idle. The AirPort (wireless LAN) was enabled and connected to a local access point less than 20 feet away.
Multitasking Battery Life
Our final battery life test is the worst case scenario. In this test we have three open Safari windows, each browsing a set of web pages with between 1—4 flash ads per page, at the same time. We're also playing an XviD video in a window all while downloading files from a server at approximately 500KB/s.
I mentioned earlier that the new 15-inch MBP has the potential to have much worse battery life given that it has twice the cores of its predecessor. Our multitasking battery life test gives you a little indication of that. At 144 minutes the new 15 lasts just under 2.5 hours here. It's only a slight reduction compared to last year's model but that's only because the workload isn't scaled up at all. OS X is likely scheduling work here across all four cores rather than just two in last year's model, driving up power consumption and decreasing battery life ever so slightly.
The new 13-inch on the other hand is pretty sweet. At 3.66 hours it's the new king of our multitasking battery life test, and it's even a slight improvement compared to the 2010 version.
Just playing back movies on the new SNB notebooks is an improvement on both models. The new 15 manages 5 hours while the new 13 is good for almost 6 hours of battery life.
Overall I'd say the battery life story of the new MacBook Pros is a mixed bag. Under light to moderate workloads the 15-inch will likely do better than the 2010 15-inch MBP, while the 13-inch is roughly the same as its predecessor. It's only under heavy use that the new 15-inch will actually do worse than last year's model. You will have to keep an eye on what you're doing with the machine because the new 15-inch MBP has the ability to use a lot more power than last year's model. The bigger issue actually has to do with the dGPU. If you use Chrome or any of the other applications that will trigger the dGPU to turn on, kiss your battery life goodbye. Even light usage suffers if your discrete GPU is active.
The new 13 is a bit less finicky. It's either going to offer you similar or better battery life than last year's model.
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zhill - Friday, March 11, 2011 - link
Good article. I was thinking about your issue with the high cpu utilization, and could it simply be a reporting issue? Could the cpu performance counters or OSX be reporting QuickSync as part of the cpu rather than the GPU? This would certainly be strange and not accurate, but given that intel seems to list QuickSync and HD3000 separately, maybe the reporting stats aren't accurate. Presumably this would be an issue in both Windows and OSX, but at the driver level there could be differences. Just a thought.Have you, or anyone else, noticed heat issues with the MBP lid closed versus open? Aren't the vent ports along the back next to the hinge such that when open they can vent, but when closed airflow could be inhibited?
Anand Lal Shimpi - Friday, March 11, 2011 - link
I thought about that too, but there seems to be a genuine increase in thermal output from the CPU - higher than I'd expect from idle cores and the quick sync engine active.I haven't personally noticed any heat issues with the lid open vs. closed, seems to behave similarly (although now that you mention it I feel like open I do get temperatures a couple of degrees cooler than when it's closed - that could just be psychological though as the comparison is completely unscientific).
Take care,
Anand
Omid.M - Friday, March 11, 2011 - link
Anand,So do the 15-17" MBPs have hardware acceleration support for Flash? I didn't see that explicitly in the review; sorry if I missed it, but I tweeted you asking for this.
The last MBP update, Anand said the 13" he could highly recommend, but the 15" got way too hot under load.
This update, Anand said the 13" he could highly recommend, but the 15" gets way too hot under load.
Hmm. (not insinuating anything, Anand and crew)
I find that odd. But, maybe it's a good thing: I'm not comfortable buying an MBP until Apple build TRIM support for 3rd party SSDs into OSX. I would not want the Apple SSDs.
My early 2008 MBP is still running fine, although I'm tempted by the QC models. Maybe waiting until Ivy Bridge, in hopes of a cooler laptop, will be enough time to see if Apple brings TRIM for after-market SSDs.
I'm disappointed, but I guess this review saved me some money until next year.
Anand Lal Shimpi - Friday, March 11, 2011 - link
Sorry I think I missed your tweet! I measured around 40 - 60% CPU utilization of a single core when viewing a 1080p HD video in YouTube on the new 15-inch MBP (same CPU usage for both the iGPU and dGPU).The frame rate was perfectly smooth, but it's unclear to me how much lifting is being done by the GPU here.
Last year's 15 was pretty warm, but this year's model definitely didn't take a step back in that department - transistor count nearly doubled after all!
The move to 22nm should bring about marginal updates to architecture so I'm hoping for lower power consumption at similar performance levels.
Take care,
Anand
Omid.M - Friday, March 11, 2011 - link
Anand,You mentioned in the last MBP refresh/review that the 13" showed support for TRIM in OSX (evidenced in System Profiler, I believe).
You also said in this refresh/review that Apple supports TRIM for its own SSDs only.
To my knowledge, the last MBP generation had the SSD option for both 13" and 15-17" models, meaning the same SSD was offered across all models.
If TRIM is only supported for Apple SSDs, why did we see an evidence of TRIM in last year's 13" model but no evidence for the 15/17, assuming the same SSD was offered across the entire line and assuming the version of OSX shipped with the last models was the same across the line?
Was that due to different chipset drivers because the 13" had the Core 2 Duo/Nvidia combo, and the older 15/17 had Core i5/i7 (thus, newer chipset) ?
Does it make sense what I'm asking?
tno - Friday, March 11, 2011 - link
Apple ships different versions (small tweaks) of OSX with different laptops, and there is the key. If you recall, the field in System Profiler was populated indicating that at some level the chipset (Nvidia sourced) supported the instruction, but SSDs that supported the instruction did not.So you're correct, Nvidia chipset driver supported TRIM, but the OS did not implement the instruction. The Core i5/i7 integrated chipset driver had no support for TRIM.
http://www.anandtech.com/show/3762/apples-13inch-m...
name99 - Friday, March 11, 2011 - link
"I saw a number of different MCS (modulation coding scheme) values with the 2011 MBP in the exact same place. Link rates from just below 300 Mbps all the way up to the expected 450. It seems to settle out at the expected 450 Mbps in the same room as the AP, it just takes a while, whereas other 2x2 stacks I've seen always lock onto 300 Mbps and stay there in the same room and position."Is the state of the art any better than this?
The reason I ask is that the simple WiFi problem (1x1 antenna, what is the best modulation + puncturing I should use for this SINR?) is well understood.
But once MIMO enters the picture there are so many more options available --- for example: should we try to use all receive antennas for different streams, and run those three streams at "robust" modulation, or should we transmit a single "fragile" (64-QAM, 5/6) stream, and rely on receive diversity to be able to detect it without error? If we send a "fragile" stream, should we use the transmit antennas to perform beam shaping to target more power at the target?
As I understand it, optimal methods for handling the juggling between all the different types of diversity available in the MIMO space still do not really exist (if anyone has a reference stating otherwise, please provide it).
If this is the case, it would not surprise if, on either the base station end, the laptop end, or both, you have a huge amount of bouncing around between different possibilities (of course with 3x3:3 the space is larger than with 2x2:2 or 2x3:2) because what is being used to make the choices are simply heuristics, not engineered algorithms, and the heuristics are extremely sensitive to the slightest changes in the SINR covariance matrix).
Brian Klug - Friday, March 11, 2011 - link
I haven't really played around enough with other 3x3 WiFi stacks enough to say for certain. I agree with you that a lot of this is it making some decisions based on whether to prioritize connection robustness or throughput rate. At close ranges, it certainly selects MCS that gives most throughput, but I'm still shocked to not see more 450 Mbps when in the exact same room as the AP.Moving away, you'll quickly fall back to single stream rates (but obviously still get MIMO range extension). You're exactly right that everyone has their own heuristics for how to do this based on SINR. I still haven't figured out how to actually grab SINR out on here, all I can see for the moment is just RSSI. Completely agreed though.
-Brian
MrCromulent - Friday, March 11, 2011 - link
Once again a very detailed, comprehensive and yet easy to understand article!I'd like to inquire once more about the C300: In the initial test, the C300 was criticized for poor garbage collection. Now it's considered an option for Apple notebooks. Has the GC been improved by Marvell in the last few firmware updates?
Griswold - Friday, March 11, 2011 - link
Interesting revenue information right at the start. Apple went from a computer- to a music&player- to a phone company. :P