Disk Performance Severely Impacted when on Battery (vs AC)

Framework Laptop 13
1

Framework 13 DIY Intel 11th Gen i5-1135G7, BIOS 03.17

Computer feels really sluggish on battery power. I was able to show that Disk speed (Samsung SSD 980 PRO 1TB) in particular is noticeably impacted:

On Battery Power:

sudo hdparm -Tt /dev/nvme0n1p2

/dev/nvme0n1p2:
 Timing cached reads:   1828 MB in  2.00 seconds = 914.97 MB/sec
 Timing buffered disk reads: 832 MB in  3.01 seconds = 276.39 MB/sec

On AC Power:

sudo hdparm -Tt /dev/nvme0n1p2

/dev/nvme0n1p2:
 Timing cached reads:   30862 MB in  2.00 seconds = 15452.98 MB/sec
 Timing buffered disk reads: 4312 MB in  3.00 seconds = 1436.76 MB/sec

Things I’ve ruled out:

  • CPU temps (I manually set the Fan to 80%, and confirmed that Temps are very low)
sudo fw-ectool temps all       
--sensor name -------- temperature -------- ratio (fan_off and fan_max) --
F75303_Local          305 K (= 32 C)           0% (313 K and 335 K)
F75303_CPU            305 K (= 32 C)           0% (313 K and 342 K)
F75303_DDR            304 K (= 31 C)           0% (313 K and 335 K)
Battery               304 K (= 31 C)           0% (313 K and 323 K)
PECI                  310 K (= 37 C)           0% (377 K and 378 K)
  • Memory usage
free -m
               total        used        free      shared  buff/cache   available
Mem:           31885        7469       21944        1517        4449       24415
Swap:          32767           0       32767
2

Here are some diagnostics on the battery:

upower -i /org/freedesktop/UPower/devices/battery_BAT1

  native-path:          BAT1
  vendor:               NVT
  model:                Framewo
  serial:               0109
  power supply:         yes
  updated:              Thu 22 Feb 2024 12:33:42 PM EST (8 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    warning-level:       none
    energy:              45.5532 Wh
    energy-empty:        0 Wh
    energy-full:         46.9238 Wh
    energy-full-design:  55.0088 Wh
    energy-rate:         4.5122 W
    voltage:             17.392 V
    charge-cycles:       195
    time to full:        18.2 minutes
    percentage:          97%
    capacity:            85.3024%
    technology:          lithium-ion
    icon-name:          'battery-full-charging-symbolic'
  History (charge):
    1708623192	97.000	charging
  History (rate):
    1708623222	4.512	charging
    1708623192	4.558	charging
    1708623169	4.605	charging
    1708623139	4.635	charging
3

Look into apst, likely something on your system limits the max power state of your ssd on battery (which may be a reasonable thing to do to improve battery life).

1 Like
4

Maybe, but that is extreme. That is 15+ times lower read throughput rates for buffers (RAM) here, and the disks are on spinning disk levels.
But to be honest, 1400MB/s is kinda slow.

@Steven_McClain Did you do these in singleuser mode?

1 Like
5

In BIOS settings there’s a setting called PCIE Dynamic Link Power Management, it’s said to reduce PCIE speed when on battery, disable it and see if that works.

1 Like
6

Well, it reduces it to PCIe gen3 speed levels if I read it well.
Just make sure nothing else runs when you do the test.