Dell XPS 15 9550 owners...what are your battery life like?

That is an interesting post, but it actually shows that something is off with the XPS 15. I tried the tool you were using and came across the following thread:
http://forum.notebookreview.com/threads/the-throttlestop-guide.531329/

The guy, who is doing the development of the tool posted: "If your computer is not achieving over 90% in a deep package C State, ask your manufacturer why."

The XPS 15 is not even getting over 5% in C6 (not just yours, but also mine)

Also see this post here:
http://forum.notebookreview.com/threads/the-throttlestop-guide.531329/page-379

Increasing the response limit for the XPS does not really help. There are simply too many interrupts.

I would be happy if others would try and tell me their C6 package readings.

 

OKAY. I just found the main culprit myself.

For everybody out there with battery life issues
Disable the dedicated NVIDIA GPU and C7 state usage will go up to 70-80%. Still not over 90%, but already much better. I might try another driver...

 

Thanks for this post. I've got a 6300HQ and I've not been using TS because the "power saver" option limits my clocks to 1300mhz on the 4-core 32m TS bench. It just won't let the clocks go up with "power saver" on. With power saver off, it seems to work fine (but it will keep clocks pegged higher and waste power).

 

A few things to keep in mind: Make sure BD Prochot is disabled, make sure you max out the multipliers and install the latest system bios, management firmwares and chipset drivers off dell's site and all that jazz.
Next, don't use any other monitoring tool than Throttlestop.
Finally, use only the Dell powerplan, and the Dell Command utility to control performance settings, don't use any other power plans.

 

Will try and report back.

 

Does Throttlestop always auto-apply undervolt settings on every fresh boot?
I am annoyed Intel XTU have problem applying my profile at times.

 

Did all that. Still didn't work. It's alright, I just unchecked the multiplier stuff.

Any reason you use a (lower) interrupt of 10 rather than the default of 18?

 

Hi,
I've found that once i exit TS, the discharge rate increases to 10W (reported by BatteryBar), and when I open it again, the discharge rate decreases to ~7W. Any ideas about this issue? Should i just keep TS opening?

 

Hi,
I've found that once I disable the 960m in device manager, the discharge rate increases immediately, though C7% does go up.
My spec: i7, FHD, 84WHr battery

 

Throttlestop auto-applies undervolts if you set the setting to do so. But it does so on throttlestop startup, not windows startup.

Yea, I accidentally touched the slider and forgot what the default was.
By the way, check your task manager for CPU consuming applications with throttlestop's c-state report open and check how having various apps open influences the core c-states.
Some apps (i'm looking at you google chrome) are a killer on the CPU, and you'll have no chance at getting reasonable battery life because your CPU will eat 4W instead of 1W and that's the end of it.

Throttlestop is great, keep it open

Yea, disabling the dGPU in device manager disables optimus, and therefore keeps the dGPU ON instead of off. Don't disable it.

 

What's your idle CPU % btw? I'm getting about 5% with the task manager open. Task manager + system and compressed memory both taking about 1.5%

 

I have a problem that my CPU never goes to 800MHz, it is stuck at 1600MHz in idle. I played now with TS, and I realized that even if I set manually multiplier to e.g 8, 9 , 10... my cpu will still run @16x100 = 1600. On the other hand if I set it to 20, 21, 22, it will run as expected @2000, 2100...
In BIOS it is properly set that minimum multiplier is 8, so I am out of ideas...

What do you think about this?

 

Are you running on the old bios, or .19?

 

.19

 

You need to have "power saver" enabled. Or disable the multiplier lock.

 

Still the same

 

Idle reported by taskmanager is <1% for me. Throttlestop reports about 4% for a single core and 2% for another. Divided by 8 makes it agree with taskmanager.

He is not the first one to report this. Please also make sure that your windows power options are set correctly.

For me it usually cannot go lower than 900 MHz. If you put the laptop to sleep and wake it up, it will be able to go down to 800MHz, but then C states 6 and 7 are getting deactivated according to Throttlestop.

Not sure what to make of it...

 

I'm not sure if these are TS bugs, Dell bugs, or skylake bugs. Lol, what a laptop...

 

Its not the TS bug, since laptop is behaving the same even without the TS.

 

Then dell better ****ing fix it

 

Regarding batteries, I saw on the manual on Dell's site that this battery only has 300 charge cycles. Anyone knows if we can replace this battery with one with greater charge cycles (once the battery inevitably dies out after a year)?

 

This is completely normal. LiIon batteries typically have a lifespan of about 300 full dis/charge cycles.

No, it's not possible to replace or "upgrade" the battery to one that has better charge cycle lifespan. This is a limitation of Li-Ion battery technology in the present day, and not based on Dell using "cheaper" or "non-premium" batteries. If and when the battery does need replacing, just buy a replacement off the internet and swap it.

BTW, the 300 charge limit is full dis/charge cycles. So unless you are running on battery every single day, and draining from 100% --> 0% every time you use your laptop on battery, the battery will last far longer than 1 year. I am a road warrior that spends about 50% of my time on the road (including heavy laptop battery use), and my laptop batteries typically start deteriorating after 2 years. At that time, they only hold 50% of the original capacity. When that happens, I just spend $80 to replace the battery (if I plan on keeping that laptop), and get another 2 years of life out of that battery.

 

I am just curious how do Macs have batteries with 1000 charge cycles?

 

If you make up your own definitions your batteries look better on paper.

 

Well my Mac battery did last more than 3 years.

 

any battery can last more than 3 years.. did it last 3 years at the same capacity as when you originally got it?

 

Yes, the life started degrading after about 3.5 years.

 

It was at about 90% capacity even at 3 years

 

I'm getting poor battery life on my UHD model with 84Whr battery. Watched a TV episode last night with VLC – 20% brightness, k/b backlight off and after the 40 minute episode my battery dropped from 100% to 62%, this doesn't seem right to me. I also did a Windows battery report and my battery is only showing a capacity of 71,341 mWh with a designed capacity of 83,995 mWh...

http://i.imgur.com/QgSDdvp.jpg

 

If anyone interested - i get 16hrs i7 FHD with two cores disabled @ 30% brightness

 

About 10 hours on my side on visual studio + browser + lot of apps, i7 FHD repasted at -150mV.

 

can you guys share your settings? I have the i7 FHD 256gb model with smaller battery. My battery at best, last about 4 hrs with minimal usage... thanks!

 

25% brightness, CPU min at 5% max 100%, screen off in 5 minutes, intel XTU -150mV, and I have had one additional hour after repasting (no more fans on half of the time).

 

Can you explain about Intel XTU and what the -150mV means? Also what thermal grease did you use?

 

thanks for the reply! do you have the 56w or 84w battery? I have offset my core voltage to -150mv, but still averages above 4hrs...

 

Intel XTU is a software where you can customize core voltage settings etc.. -150mv refers to offsetting core voltage to -150mv

 

Exactly !

For the thermal paste & pads, I used grizzly kryonaut paster and 2mm grizzly minus pad 8.
I'm on the 84w battery

 

I have an XPS 15 9550 with 6th gen i7 quad core with a 4K touch screen, 16GB RAM, 256 SS drive and Windows 10. Battery life is 4 hrs. 50 minutes when brightness is set at 25% and resolution set at FHD, and only doing mild web surfing and e-mail. NOT GOOD!!!! Needless to say, I'm very disappointed. Had I known that a 4K screen would affect the battery life that much, I would not have chosen this computer. But Dell Sales doesn't say a word about that, so I had no idea. Not knowing any better, I was actually expecting to get something near to the 17 hr. battery life they advertise, which I think is a fraudulent claim.

 

Check your background programmes using CPU. Should idle at 0-1%.

 

What does -150mv actually do for the Skylake i7 though? I had a quick search online and some say better performance with lower vcore in laptops so how does that make battery life better?

Also, is there a guide for repasting on the 9550?

 

Lower volts with same amperes = lower watts. Default @100% CPU usage = 45w, with -150mv = 37w.
Simple as that

 

I know the maths, but why is this originally powered with that voltage and not less?

 

In order to prevent CPU instability with some margin. Each CPU react in a different way under undervolting. Some can be unstable at -160mv, some at -180mv, and some at -50mv... It's a warranty for Intel to deliver working CPUs.
The same applies to overclocking : the i7 6700K is sold for 4Ghz, most people can overclock it to 4,2 Ghz, not everyone can overclock it to 4,8 Ghz

 

So when you do -150mV does your vcore change as opposed to stock?

 

-150mV are applied to vCore, so yes

 

Does it lower clock speed? Also are there any guides for repasting?

 

At each frequency, there is a certain voltage that is required to run the circuitry on your CPU. That voltage is unique to each chip due to random variations in manufacturing between chips. Without getting into too much detail, the stock voltage is set higher than necessary to provide headroom for this variation (and degradation that occurs as a result of aging).

Decreasing this voltage from the stock setting does not have impact on performance at a fixed frequency because your performance is only a function of frequency. However too low of a voltage can cause instability (i.e. the circuits begin to produce errors at too low of a voltage). This is why it's important to stress test your undervolt at low and high voltages to make sure your CPU works at all operating points.

In the case where your CPU is throttling (reducing frequency) because it is too hot, reducing the voltage can improve average performance. By reducing the voltage, you will be producing less power and thus less heat. This means your CPU will spend more time at a higher average frequency. Once you're not thermally throttling, adjusting voltage won't have any impact on performance (at stock frequencies).

Also, CPU power can be broken down into two large buckets: dynamic power and leakage power. Dynamic power scales with frequency and voltage, leakage power scales with voltage and temperature. Reducing voltage reduces both of these components of power, while reducing frequency and temperature only reduce one.

To minimize your CPU power, you ideally want to run at the lowest voltage and temperature possible, and the lowest frequency that doesn't negatively impact your performance.

Let me know if you want more details on this and I can try to answer some questions.

 

Thanks for the in depth response, I've done a lot of overclocking but no underclocking, I'll have a play around tonight.
Does underclocking affect the GPU at all?

 

Also do does repasting void warranty?

 

The Dell service manual is available from Dell to answer your 1st question & to answer the 2nd, no but any physical damage you cause during will.

Not the Nvidia one.