Various thinkpads, MX19 vs MX21 power consumption, kernel differences?
Posted: Sun Jan 02, 2022 4:50 pm
Happy new year everyone.
I am setting up Home Assistant server for our new home. I also have a weird hobby and collect older ThinkPad laptops. I thought I would use an older Thinkpad X61T (tablet) to run the Home Assistant server. This Core2Duo laptop, bundeled with the MX21 FLuxbox edition, is a great option and serves the purpose very well. However, I discovered that the power consumption is rather high even considering this ancient technology.
I used an external wattmeter that measures the real power consumed by the laptop. All batteries are removed, wifi is off (HW switch). I identified there is a big difference between MX19 (xfce) and MX21 (xfce) distros. I know that MX21 uses the newer kernel. Still, I would expect the difference being smaller. Using powertop revealed that this maybe not be CPU-related. The CPU stays practically constantly at the lowest clock.
x61t (c2d ULV CPU) - closed lid, bootable USB with MX21, no internal HDD, "sudo tlp bat" to force power saving - 12.6-13.6W
x61t (c2d ULV CPU) - as above but with MX19 - 9.15-9.3W
x61 (c2d)- closed lid, bootable USB with MX21, internal SSD installed, "sudo tlp bat" to force power saving - 11.98-12.18W
x61 (c2d)- as above but with MX19 - 8.15-8.6W
x230 i5 Ivy Bridge- closed lid, official windows 7 preload, internal SSD, highest battery saving available from windows 6.86-7.27W
x230 i5 Ivy Bridge- same as above but with MX21 from live USB, "sudo tlp bat" to force power saving 8.02-8.3W
x230 i5 Ivy Bridge- same as above but with MX19 7.45-8.3W
x301 (c2d, SU series)- closed lid, bootable USB with MX21, internal SSD installed (but unused), "sudo tlp bat" to force power saving - 11.05-11.5W
x301 (c2d, SU series)- same as above but MX19.1runing from the internal SSD 8.55-8.63W
x301 (c2d, SU series)- same as above but MX19 running from the bootable USB 8.83-8.86W <-no significant difference if run from SSD or from USB
x240 (i5, ULV Haswell)- closed lid, bootable USB with MX21, no internal drive, "sudo tlp bat" to force power saving - 2.7-3.8W (WHAT A DIFFERENCE!)
x240 (i5, ULV Haswell)- ame as above but MX19 - 2.15-2.30W (WHAT A DIFFERENCE!)
This exercise is not about absolute numbers but rather about comparison. Pretty much all laptops with different configurations confirmed that MX21 draws more power than MX19. For certain models such as x61, it is 33% more. I live in Germany and electricity is not cheap. 10W of difference over one year pays off a second-hand Intel NUC. Still, I really love the idea of having the x61t running the home. (intrinsic UPS, touch screen, very nerdy and lovely device).
I would like to kindly ask for an advice on how to debug the power consumption further. I appreciate any tips.
Thank you, Jiri
PS: I tried 4.19 AntiX kernel from the repo. The power consumption dropped a bit (for x61t) but definitely not below 10W as it should be.
I am setting up Home Assistant server for our new home. I also have a weird hobby and collect older ThinkPad laptops. I thought I would use an older Thinkpad X61T (tablet) to run the Home Assistant server. This Core2Duo laptop, bundeled with the MX21 FLuxbox edition, is a great option and serves the purpose very well. However, I discovered that the power consumption is rather high even considering this ancient technology.
I used an external wattmeter that measures the real power consumed by the laptop. All batteries are removed, wifi is off (HW switch). I identified there is a big difference between MX19 (xfce) and MX21 (xfce) distros. I know that MX21 uses the newer kernel. Still, I would expect the difference being smaller. Using powertop revealed that this maybe not be CPU-related. The CPU stays practically constantly at the lowest clock.
x61t (c2d ULV CPU) - closed lid, bootable USB with MX21, no internal HDD, "sudo tlp bat" to force power saving - 12.6-13.6W
x61t (c2d ULV CPU) - as above but with MX19 - 9.15-9.3W
x61 (c2d)- closed lid, bootable USB with MX21, internal SSD installed, "sudo tlp bat" to force power saving - 11.98-12.18W
x61 (c2d)- as above but with MX19 - 8.15-8.6W
x230 i5 Ivy Bridge- closed lid, official windows 7 preload, internal SSD, highest battery saving available from windows 6.86-7.27W
x230 i5 Ivy Bridge- same as above but with MX21 from live USB, "sudo tlp bat" to force power saving 8.02-8.3W
x230 i5 Ivy Bridge- same as above but with MX19 7.45-8.3W
x301 (c2d, SU series)- closed lid, bootable USB with MX21, internal SSD installed (but unused), "sudo tlp bat" to force power saving - 11.05-11.5W
x301 (c2d, SU series)- same as above but MX19.1runing from the internal SSD 8.55-8.63W
x301 (c2d, SU series)- same as above but MX19 running from the bootable USB 8.83-8.86W <-no significant difference if run from SSD or from USB
x240 (i5, ULV Haswell)- closed lid, bootable USB with MX21, no internal drive, "sudo tlp bat" to force power saving - 2.7-3.8W (WHAT A DIFFERENCE!)
x240 (i5, ULV Haswell)- ame as above but MX19 - 2.15-2.30W (WHAT A DIFFERENCE!)
This exercise is not about absolute numbers but rather about comparison. Pretty much all laptops with different configurations confirmed that MX21 draws more power than MX19. For certain models such as x61, it is 33% more. I live in Germany and electricity is not cheap. 10W of difference over one year pays off a second-hand Intel NUC. Still, I really love the idea of having the x61t running the home. (intrinsic UPS, touch screen, very nerdy and lovely device).
I would like to kindly ask for an advice on how to debug the power consumption further. I appreciate any tips.
Thank you, Jiri
PS: I tried 4.19 AntiX kernel from the repo. The power consumption dropped a bit (for x61t) but definitely not below 10W as it should be.