Surface Pro: Underclocking to increase battery life?

[mkumar12345]

I am considering buying a Surface Pro, but am concerned about it's battery life. From what I have seen, it averages around 4-5 hrs max of on-screen time with varied use and that is simply not enough for me.

However I would be happy if it lasted 6-7 hrs. I was wondering how Acer Iconia W700 is able to achieve ~7 hrs battery life with very similar specs as Surface Pro with only a slightly larger battery. My guess is that the CPU/GPU here is underclocked and not having a Wacom digitizer surely helps a bit too.

I am not as concerned with the speed of the machine as I do fine with clover trail convertibles. I just like the Surface Pro form factor more and need x86 and wacom compatibility.

So here are my questions:
1) How can we underclock the CPU/GPU on the Surface Pro, i.e. is there an easy to use software available to do this safely? Do you think it will work to reduce the power consumption and increase battery life (and by how much)?

2) Is there a way to turn-off the Wacom digitizer? On my galaxy note 2 there is a setting to turn it off, and it does help add to the battery life. There has to be some setting for a Windows machine as well, but I don't know where it is.

 

[poofyhairguy]

From what I have seen, it averages around 4-5 hrs max of on-screen time with varied use and that is simply not enough for me.

However I would be happy if it lasted 6-7 hrs.

That should be achievable in the next generation of Surface Pros.

 

[dagamer34]

Don't bother. I already tried this when I had a Surface Pro for a month. Ivy Bridge uses too much in total platform power for this to be effective. If the system has an idle CPU, min brightness, WiFi on (but not transmitting) it only lasts 8 hours 13 minutes. Jack that up to 50% brightness and it's 6hrs 13 minutes (again, idle CPU). The CPU automatically down clocks itself when in power saver mode, no special software needed.

Wait for Haswell.

 

[zerogear]

From what I've heard MS is going AMD for 2nd generation Surface Pro. AMD Temash, iirc.

 

[Bateluer]

Don't bother. I already tried this when I had a Surface Pro for a month. Ivy Bridge uses too much in total platform power for this to be effective. If the system has an idle CPU, min brightness, WiFi on (but not transmitting) it only lasts 8 hours 13 minutes. Jack that up to 50% brightness and it's 6hrs 13 minutes (again, idle CPU). The CPU automatically down clocks itself when in power saver mode, no special software needed.

Wait for Haswell.

I believe the Surface Pro uses Sandy?

 

[dagamer34]

I believe the Surface Pro uses Sandy?

Surface Pro is Ivy Bridge: http://www.anandtech.com/show/6695/microsoft-surface-pro-review

 

[Mopetar]

The screen is going to eat up more battery than just about anything else in the device, so you'll get more from using it at a lower brightness than reducing the clock on the CPU. Also, unless you undervolt it as well, you might not get too much of a gain from just dropping the clock. A slower clock just means it takes the CPU longer to finish whatever its doing before it can drop back to idle.

You could try downloading Intel's XTU and giving it a spin. I don't think that you'll get too much in the way of additional battery life, but it still might be worth it for you.

 

[runawayprisoner]

The screen is going to eat up more battery than just about anything else in the device, so you'll get more from using it at a lower brightness than reducing the clock on the CPU. Also, unless you undervolt it as well, you might not get too much of a gain from just dropping the clock. A slower clock just means it takes the CPU longer to finish whatever its doing before it can drop back to idle.

You could try downloading Intel's XTU and giving it a spin. I don't think that you'll get too much in the way of additional battery life, but it still might be worth it for you.

Actually, on an x86 device, it's the CPU that east up more battery than anything else. A screen on average consumes about 2.5W, but the CPU and chipset will happily gorge 5-10W.

It's doubly true as Intel moves closer to a true SoC solution.

 

[dagamer34]

The screen is going to eat up more battery than just about anything else in the device, so you'll get more from using it at a lower brightness than reducing the clock on the CPU. Also, unless you undervolt it as well, you might not get too much of a gain from just dropping the clock. A slower clock just means it takes the CPU longer to finish whatever its doing before it can drop back to idle.

You could try downloading Intel's XTU and giving it a spin. I don't think that you'll get too much in the way of additional battery life, but it still might be worth it for you.

I've already stated that a Surface Pro idling, doing absolutely nothing, with min brightness, doesn't approach the battery life of what an iPad 4 does during active use with 50% brightness (8hrs vs 10hrs) and they have very similar battery sizes. The system uses too much power at idle.