Sager power consumption

Hey there! So, as of now i'm a lucky owner of Sager NP8250-S with 4800MQ + 780M) While having a regular cheap Kill-A-Watt meter around i've decided to do a little interesting measurements of power consumption of different components of the system. The reason behind this is that the 180W PSU stuggles to hold the system overclocked and i had to calculate which settings are the most suitable for my gaming/benchmarking sessions

All the test were run under 3DMark11 Performance - 1st GPU tets. It seemed that it stresses the system most, not even 3DMark Vantage or 3DMark13 or, and that's weird, 3DMark11 Extreme could push it to the limits that much.

So here's a little guide on how to save/calculate power draw (PD) on a laptop like this (the others may follow the suit):

GPU:

- Bumping 0.05mV on the core adds 10-11W to PD, undervolting by the same margin saves same 10-11W
- Bumping +50Mhz on the core adds 5-6W to PD
- Bumping +100Mhz on the memory adds 1W to PD

CPU:

Using Intel XTU i was able to move the offset values down to -100mV that saved 13W of PD and 2-3C

SYSTEM:

- FN+1 (fans on max) adds 3.5W to PD
- Keyboard backlit from completely off to all the way bright adds 3.5W as well
- Difference between LCD dimmed to min and turned on max - 7W to PD

I flashed 780M with svl7 custom vbios so could easily OC the beast on the fly. Anyways those simple calculations helped with achieve some great results with OC! I hope it does to you as well) For daily use i undervolt CPU by 100mV and GPU by 0.05mV and am really happy with the results and a little decrease in temps! The laptop is just a pleasure to play with :thumbsup:

 

Repped u for the effort of sharing this info with us.

 

+ rep back) i hope it will help someone!

 

Keep in mind also that if the measurement is on the AC side of the power it is not 100% accurate.

If I recall correct these PSU are around around the 80-87% efficiency mark depending on load.

 

Yes but measuring the difference will only have that small error in it.

 

That keyboard backlighting draws more than I expected, bravo for these measurements. So you saved ~23 watts and 2.5C? Thats not bad at all. When do you turn the settings back up, and how often? Is it inconvenient at all?

 

knoth I think i saved 2-3C on CPU and 3-5C on GPU as well) I usually use -100mV on CPU and -0.05mV on GPU, cause the system runs a little quiter as well, it just doesn't have to crank the fans up if the temps are not that high!

When i played crysis 3 on stock settings the system drew about 180W as is! No OC, UV. Now i can UV CPU, turn the KB backlit and still have room for a +150Mhz OC on the GPU core which will boost the game by 15%. And that's exactly what i need)

You know what they say: OC, UV at your own risk! Some chips may fail with these settings and some won't. This is how i want to check the system MAX abilities in both OC and UV, it's just for fun)