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I have a cheap Linx 10v64 tablet - Intel Atom x5-z8300, 4GB RAM, 64 GB eMMC module.
I am considering enabling bitlocker on the main (OS) drive but am concerned about the effect on performance given the modest specs of the machine.
I made a 7GB partition for test purposes, and ran CrystalDiskMark :
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CrystalDiskMark 5.2.0 x64 (C) 2007-2016 hiyohiyo
Crystal Dew World : http://crystalmark.info/
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* 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) : 140.647 MB/s
Sequential Write (Q= 32,T= 1) : 89.082 MB/s
Random Read 4KiB (Q= 32,T= 1) : 33.730 MB/s [ 8234.9 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 15.586 MB/s [ 3805.2 IOPS]
Sequential Read (T= 1) : 156.034 MB/s
Sequential Write (T= 1) : 96.884 MB/s
Random Read 4KiB (Q= 1,T= 1) : 10.380 MB/s [ 2534.2 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 15.317 MB/s [ 3739.5 IOPS]
Test : 1024 MiB [E: 0.4% (26.4/7167.0 MiB)] (x5) [Interval=5 sec]
Date : 2016/11/15 21:52:26
OS : Windows 10 Professional [10.0 Build 14393] (x64)
I then enabled bitlocker on the partition, and ran again:
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CrystalDiskMark 5.2.0 x64 (C) 2007-2016 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) : 154.574 MB/s
Sequential Write (Q= 32,T= 1) : 92.137 MB/s
Random Read 4KiB (Q= 32,T= 1) : 33.680 MB/s [ 8222.7 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 16.052 MB/s [ 3918.9 IOPS]
Sequential Read (T= 1) : 120.384 MB/s
Sequential Write (T= 1) : 70.879 MB/s
Random Read 4KiB (Q= 1,T= 1) : 8.561 MB/s [ 2090.1 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 13.000 MB/s [ 3173.8 IOPS]
Test : 1024 MiB [E: 0.4% (26.6/7167.0 MiB)] (x5) [Interval=5 sec]
Date : 2016/11/15 22:07:10
OS : Windows 10 Professional [10.0 Build 14393] (x64)
I was surprised to see that while some of the measured speeds are slower, the sequential tests with multiple queues are a little faster.
How could this be? I thought bitlocker represented an overhead on the processor - which in this case is only an Atom.
interesting idea - is it documented anywhere that bitlocker does any compression? that might even be a plus with such a small 'disk'! – topo Reinstate Monica – 2016-11-15T23:02:47.823
No, I haven't seen anything written on compression, but you might experiment by checking actual file size, encrypted vs. unencrypted. However, Windows may be reporting the size for encrypted files as they would appear after encryption, so you'd need to check with some disk tool other than Windows Explorer (or CMD dir). – DrMoishe Pippik – 2016-11-15T23:08:44.727