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SP4 M3 vs. SP4 i5 - My Own Battery Life Face Off

I would love to not carry my charger when I board a plane from HI to CA. But if I play around web browsing on my old SP2 for an hour before take off, I'll already be 70% or less. Then I watch a movie for two hours, I wouldn't have much battery if at all. I really wish manufactures in general would quote battery life better."
Example: Get an average person who knows a bit about PC computers. Hand him the computer and say browse the internet/watch a movie/play an app or something. Then see how long the battery lasts. Get three or four people. And get an average. Now we know. But that ain't going to happen. They will run the test in a lab and see what's the best time doing the least amount of stuff that still looks like we're using the notebook gets.

Of course, let's say that MS does an honest mixed usage battery test, and says "you'll get 5 hours of battery life" and then HP or Dell says "12 hours" haha. What do you think MOST people will think?

Regardless, I just checked their website and they state "2 Hasta 9 horas de reproducción de vídeo." Sorry, local Spanish site came up. And it says it's 9 hours of video. I saw someone get around 8 hours of video testing, so I think this is completely doable and realistic. The thing is, we test video, downloading, browsing, commenting, painting, etc. It's NOT just sitting down and watching a show or movie for 8-9 hours straight, with no other apps or processes loaded into RAM. You know?
 
I have in my possession both the SP4 M3 and the SP4 i5 (4GB/128BG) for the next week. So I decided to run my own battery life comparison.

I consider the following results just a dry run. I plan to run these 2 PCs until they shut down sometime this weekend.

I went to endlessvideo.com and picked the same video to run on both PCs. When I came home from work today, I turned off the sound (to keep my sanity) and just let them run from a fully charged state.

1 hr 3 min -- i5 87% remaining -- M3 89% remaining
2 hr 5 min -- i5 73% remaining -- M3 76% remaining
3 hr 0 min -- i5 60% remaining -- M3 65% remaining

I think I may have handicapped the i5 a bit because I had 4 other Edge tabs open at the start. I closed those 4 extra tabs about 5 minutes after the start.

I'm no tech expert, so if anyone has any suggestions about how to make the comparison more fair, please let me know so I can do the best possible test this weekend.

Unfortunately what you can't control, background processes, can affect battery life more than the test you are running. Things like windows update, windows search indexing, anti-virus, windows defender scans, etc. will all affect cpu usage and battery life. You are controlling what you see, but there are so many things going on in the background that it's really a mixed bag.
 
Unfortunately what you can't control, background processes, can affect battery life more than the test you are running. Things like windows update, windows search indexing, anti-virus, windows defender scans, etc. will all affect cpu usage and battery life. You are controlling what you see, but there are so many things going on in the background that it's really a mixed bag.

What you say is true! I guess the best way to test THAT is to either let your PC run for a while without doing anything to let indexing run, updates run, with no personal programs running

OR

Refresh your device so it's only BASIC windows. With no personal configuration, no data...

But come on, this is all very "personal..." Every person is going to have different times, but this is a good idea of how long... An antivirus won't be running scanning everything if you leave your PC Idle unless you're also telling it to run! Indexing is limited, so, once it's done after a refresh, then it's done.

Regardless, I'm getting between 5-7 hours, and I'm happy. Love the device.
 
I updated both the M3 and the i5(4GB/128GB) for the latest updates (12/17). I opened 3 windows on both SP4s (Settings, Surface and Edge) and 3 Edge tabs (Yahoo, TechBargains and endlessvideo.com). Once both SP4s were fully charged, I started the same video (with muted sound for my sanity) and then unplugged them. Here are the results:

1 hr 0 min -- i5 84% remaining -- M3 86% remaining
2 hr 0 min -- i5 65% remaining -- M3 70% remaining
3 hr 0 min -- i5 49% remaining -- M3 55% remaining
4 hr 0 min -- i5 32% remaining -- M3 40% remaining
5 hr 0 min -- i5 15% remaining -- M3 28% remaining

If we look at usage (100% minus the above results), we can compare battery consumption.

1 hr 0 min -- i5 16% usage -- M3 14% usage (i5 consumed 14% more battery power)
2 hr 0 min -- i5 35% usage -- M3 30% usage (i5 consumed 17% more battery power)
3 hr 0 min -- i5 51% usage -- M3 45% usage (i5 consumed 13% more battery power)
4 hr 0 min -- i5 68% usage -- M3 60% usage (i5 consumed 13% more battery power)
5 hr 0 min -- i5 85% usage -- M3 72% usage (i5 consumed 18% more battery power)

The SP4 shuts down when the battery has 3% remaining life. If we look at the total battery life for this test, the results are:

i5 -- 5 hours 49 minutes (total minutes = 349)
M3 -- 6 hours 38 minutes (total minutes = 398)

Therefore, in this test, the M3 battery life exceeded the i5 battery life by 14% (398/349 minus 100%). Note that I did not hear the i5 fan come on during this test.

These results are very similar to the dry run results I posted at the beginning of this thread, in that, the i5 consumed about 14% total more power than the M3. The battery times are in this test are shorter than the previous test because I had more apps/tabs open during the test, which puts additional draw on the batteries.

The i5 consistently consumes about 14% more battery life than the M3. The SP4 has limited battery life to begin with. Based on these results, I am leaning towards the M3 because I would rather have 14% more battery life than the added speed. Those are my priorities. You may read these results and prefer the i5 based on your priorities. Just remember, the i5 is not just costing you an extra $100, it's costing you about 14% of your battery time, too.
 
The two biggest consumers of battery power are the display and the CPU/system, in that order. The display consumption is relatively constant, while the CPU/system consumption is the primary variable here. The two factors affecting CPU/system battery consumption are the specific components (M3 vs. i5) and individual usage (e.g., processor intensive apps, etc.)

After I ran this test and studied the results, something occurred to me. While the test results consistently showed that the M3 gets about 14% more battery time, these results are based on a certain level of CPU/system usage. If actual CPU/system usage is more than was experienced in this test, then one would expect that that difference in battery life between the M3 and i5 would be greater than 14%. Conversely, if actual CPU/system usage is less than was experienced in this test, then one would expect that that difference in battery life between the M3 and i5 would be less than 14%.

Fortunately, the SP4 has a very nice summary of battery usage. See Settings => System => Battery Saver => Battery use

So I took a look at this summary. The allocation of battery usage was:

i5 24 hour System -- 55%
i5 24 hour Display -- 44%
i5 24 hour Wi-Fi -- 2%

i5 48 hour System -- 32%
i5 48 hour Display -- 67%
i5 48 hour Wi-Fi -- 2%

i5 1 Week System -- 31%
i5 1 Week Display -- 67%
i5 1 Week Wi-Fi -- 2%


M3 24 hour System -- 8%
M3 24 hour Display -- 91%
M3 24 hour Wi-Fi -- 1%

M3 48 hour System -- 9%
M3 48 hour Display -- 90%
M3 48 hour Wi-Fi-- 1%

M3 1 Week System -- 9%
M3 1 Week Display -- 90%
M3 1 Week Wi-Fi -- 1%

Note that the 24 hour results do not include the 6 hour face off I posted on 12/19. while the 48 hour and 1 week results include that test. Therefore, the 24 hour test is a pure reflection of my actual usage, while the 48 hour and 1 week results are a hybrid, but primarily reflect the 6 hour face off.

Overall, it amazes me how little power the M3 CPU/system uses. This is an amazing little chip. The data above indicates that the M3 consumes about 20% to 30% of the battery power compared to the i5.

Lastly, the above results indicate that my actual CPU/system usage is significantly more than was utilized during the test. Therefore, my M3 battery life under actual usage will be significantly more than 14% better than the i5.
 
You're making me want to return my i5 and go for an M3 ;) haha.


The two biggest consumers of battery power are the display and the CPU/system, in that order. The display consumption is relatively constant, while the CPU/system consumption is the primary variable here. The two factors affecting CPU/system battery consumption are the specific components (M3 vs. i5) and individual usage (e.g., processor intensive apps, etc.)

After I ran this test and studied the results, something occurred to me. While the test results consistently showed that the M3 gets about 14% more battery time, these results are based on a certain level of CPU/system usage. If actual CPU/system usage is more than was experienced in this test, then one would expect that that difference in battery life between the M3 and i5 would be greater than 14%. Conversely, if actual CPU/system usage is less than was experienced in this test, then one would expect that that difference in battery life between the M3 and i5 would be less than 14%.

Fortunately, the SP4 has a very nice summary of battery usage. See Settings => System => Battery Saver => Battery use

So I took a look at this summary. The allocation of battery usage was:

i5 24 hour System -- 55%
i5 24 hour Display -- 44%
i5 24 hour Wi-Fi -- 2%

i5 48 hour System -- 32%
i5 48 hour Display -- 67%
i5 48 hour Wi-Fi -- 2%

i5 1 Week System -- 31%
i5 1 Week Display -- 67%
i5 1 Week Wi-Fi -- 2%


M3 24 hour System -- 8%
M3 24 hour Display -- 91%
M3 24 hour Wi-Fi -- 1%

M3 48 hour System -- 9%
M3 48 hour Display -- 90%
M3 48 hour Wi-Fi-- 1%

M3 1 Week System -- 9%
M3 1 Week Display -- 90%
M3 1 Week Wi-Fi -- 1%

Note that the 24 hour results do not include the 6 hour face off I posted on 12/19. while the 48 hour and 1 week results include that test. Therefore, the 24 hour test is a pure reflection of my actual usage, while the 48 hour and 1 week results are a hybrid, but primarily reflect the 6 hour face off.

Overall, it amazes me how little power the M3 CPU/system uses. This is an amazing little chip. The data above indicates that the M3 consumes about 20% to 30% of the battery power compared to the i5.

Lastly, the above results indicate that my actual CPU/system usage is significantly more than was utilized during the test. Therefore, my M3 battery life under actual usage will be significantly more than 14% better than the i5.
 
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