Laptop Hard Drive Speed Oddness

[Jonj1611]

This has been a bit confusing if i'm honest.

My laptop hard drive runs slower when PLUGGED IN than when running battery.

What kind of witchcraft is this?

Several crystal mark tests show it runs between 2 and 15mb slower when plugged in than when on battery.

Any ideas?

[adidan]

I can only think it may be something to do with how your power plan is set up as it is often different when plugged in to when it's on battery.

May be worth looking in there to see if there's anything that stands out. Could always mimic your battery plan and test if the difference is still present.

I've always found laptops to be the oddest of pc tech, they always have some random quirk that stumps you.

[Jonj1611]

First place I looked. All normal there

[MaddAussie]

How long after pulling the plug are you doing the tests? Could the HDD be slightly cooler as the laptop as a whole is not generating as much heat? Just a guess... you could try monitoring its SMART...

[Jonj1611]

The laptop isn't very old, its a Dell from the Dell outlet, means its a returned unit, all perfect condition but did notice the hard drive had been turned on 118 times according to smart. Anyway the laptop as always run stupidly slow and for a 2016 laptop thats not very good. The other day I turned it on and was surprised how quick it was going, boot up time etc was so much faster. At that point I realised I hadn't plugged it in and it was running off the batteries.

So did a crystal mark test and then plugged it in and ran it again, it was quicker off the battery. Run a surface scan etc, checked the smart, nothing wrong with the drive apparently, but its notably quicker just on batteries. Checked power settings and they are as they should be so i'm a bit stumped to be honest.

[adidan]

First place I looked. All normal there

Sorry, had to ask. Will ponder on this, does seem odd.

[Jonj1611]

I agree, generally things get quicker when plugged in, not slower :/

[Taz]

Just thinking out loud: I wonder if the laptop shuts down some services when on battery power? Maybe check process list to see what's different?

[Jonj1611]

Ignoring the read, look at the writes. First one is on battery, second one is on mains.

-----------------------------------------------------------------------
CrystalDiskMark 5.2.2 x64 (C) 2007-2017 hiyohiyo
Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

Sequential Read (Q= 32,T= 1) : 96.514 MB/s
Sequential Write (Q= 32,T= 1) : 95.500 MB/s
Random Read 4KiB (Q= 32,T= 1) : 0.648 MB/s [ 158.2 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 0.778 MB/s [ 189.9 IOPS]
Sequential Read (T= 1) : 95.842 MB/s
Sequential Write (T= 1) : 91.440 MB/s
Random Read 4KiB (Q= 1,T= 1) : 0.276 MB/s [ 67.4 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 0.709 MB/s [ 173.1 IOPS]

Test : 1024 MiB [C: 4.8% (41.6/869.0 GiB)] (x5) [Interval=5 sec]
Date : 2017/09/07 21:03:49
OS : Windows 10 [10.0 Build 15063] (x64)


-----------------------------------------------------------------------
CrystalDiskMark 5.2.2 x64 (C) 2007-2017 hiyohiyo
Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

Sequential Read (Q= 32,T= 1) : 97.684 MB/s
Sequential Write (Q= 32,T= 1) : 88.017 MB/s
Random Read 4KiB (Q= 32,T= 1) : 0.659 MB/s [ 160.9 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 0.733 MB/s [ 179.0 IOPS]
Sequential Read (T= 1) : 97.521 MB/s
Sequential Write (T= 1) : 67.526 MB/s
Random Read 4KiB (Q= 1,T= 1) : 0.296 MB/s [ 72.3 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 0.688 MB/s [ 168.0 IOPS]

Test : 1024 MiB [C: 4.8% (42.1/869.0 GiB)] (x5) [Interval=5 sec]
Date : 2017/09/07 21:47:59
OS : Windows 10 [10.0 Build 15063] (x64)

[satrow]

Some AVs can be set so that any background/idle scans are disabled on battery power.

Does Resource Manager show any differences between mains and battery drive access at idle?