Tuesday, 17 January 2017

Which is best, the SanDisk Extreme Pro or the cheaper SanDisk Extreme (you may be surprised!)?

Hurray! My new SanDisk Extreme Pro USB 3.0 128GB flash drive just came this morning.

Extreme Pro 128GB $70
Extreme 128GB $60

I have now run a few tests on it and compared it directly with the SanDisk Extreme USB 3.0 64GB flash drive.

I tested the Pro using Crystal DiskMark and then filled to entire drive with junk data and then repeated the test. This ensured that the flash controller had to perform a read-erase-write cycle on every write when running any further tests. However, there was no difference between benchmarks after I had filled it with junk data and then re-formatted it. This indicates that the USB controller always does a read-erase-write cycle on every write (so not an SSD controller).

The Crystal DiskMark results are shown below:

Extreme Pro 128GB
Extreme 64GB

The results were similar (but they did vary a fair bit when repeated).

I copied 3 large files from my internal SSD to each USB drive (using Xcopy from the command line) and calculated the transfer rates:

Extreme Pro 128GB: 211 MB/s
Extreme         64GB: 147 MB/s

XP Pro ISO extraction
I extracted the 1000's of small files from a XP Pro SP3 ISO onto each drive using 7Zip.

Extreme Pro 128GB: 33 secs
Extreme         64GB: 75 secs

Make E2B+DPMS drive
I ran MAKE_E2B_USB_DRIVE (run as admin).cmd and timed it:

Extreme Pro 128GB: 31 secs
Extreme         64GB: 60 secs

Booting to E2B
I booted each flash drive to E2B on an IdeaPad 300 and a USB 3.0 port. The SanDisk Extreme 64GB was noticeably faster (probably twice as fast, though I did not time it because they did not have identical contents).

Grub4dos File Access times
I ran the E2B - Utilities - Measure BIOS USB Performance test on each drive on the IdeaPad 300 USB 3.0 port for 1000 cycles:

Extreme Pro 128GB: 29 secs
Extreme         64GB: 14 secs    << FASTER!

Boot to WinPE
When booting to WinPE from an ISO, I noticed little difference (14 seconds for each).
When booting to a full Windows 10 .VHD file, the Pro was approx. 1 second faster (15\16 seconds).
Performance when running Windows To Go was markedly different however! The Pro seemed much 'snappier'. I ran Crystal DiskMark on the VHD's C: drive and D: Flash drive (both, of course, accessed the USB drive) and got these results (but they varied widely when repeated and so should be taken with a pinch of salt!):

WinToGo C: (VHD on Flash drive)
                    Extreme Pro 128GB              Extreme 64GB
               Read (MB/s)   Write (MB/s)   Read (MB/s)   Write (MB/s)
Seq (Q32T1)    198           29             174           14
4K (Q32T1)     9.53          3.4            6.35          1.9
Seq            206           44.2           47            24
4K             7             4.4            1.6           4.6
WinToGo D: (USB Flash drive)
                    Extreme Pro 128GB              Extreme 64GB
               Read (MB/s)   Write (MB/s)   Read (MB/s)   Write (MB/s)
Seq (Q32T1)    184           40             181           24    
4K (Q32T1)     7.6           5.5            7.6           9.1
Seq            222           23             166           20
4K             7             5.7            5             6.4

H2benchw benchmarks (under Windows 10 x64 with Z87 mainboard)

Extreme Pro results are in bold:

Inateck FE2007 USB 3 enclosure + Samsung 500GB 850 EVO in Green for comparison.

Disk:         SanDisk Extreme                                  SanDisk Extreme Pro                         Samsung 850 EVO 500GB
Capacity:   125033895 sectors = 61052 MByte   250083855 sectors = 122111 MByte    976768065 sectors=476938 MByte

Interface transfer rate w/ block size 128 sectors at 0.0% of capacity:
Sequential read rate medium (w/out delay):                    176,993 KByte/s   174,780 KByte/s   260.4 MByte/s
Sequential transfer rate w/ read-ahead (delay: 0.40 ms): 180,081 KByte/s  173,695 KByte/s    263.3 MByte/s
Repetitive sequential read ("core test"):                            49,882 KByte/s     66,296 KByte/s    188.5 MByte/s

Random access read:  average 0.50, min 0.25, max 0.74 [ms]
                                   average 0.58, min 0.34, max 0.98 [ms]                                  
                                    average 0.11  min. 0.05, max. 0.21 [ms]

Note that the Random Access time and non-repetitive sequential xfer rates for the cheaper Extreme are better than the Pro!


Under Windows, the Extreme Pro is certainly faster, both for large files and small files. However, under grub4dos, BIOS access is much slower than the cheaper SanDisk Extreme.

However, if you use E2B a lot and need to boot to the E2B menus as quickly as possible to run diagnostic software, etc., I would recommend the cheaper SanDisk Extreme.

If you regularly copy lots of different files to your E2B drive under Windows (e.g. large VHDs or ISOs) the Extreme Pro will certainly take less time to copy them over than with the SanDisk Extreme. Running WindowsToGo will also be faster, as should full linux installations or linux+persistence. If booting from an E2B USB drive using Virtual Box, the Pro should be faster too.

There is no clear winner, the choice is yours...

Note: In this blog post, I have compared a SanDisk Extreme 64GB drive with a SanDisk Extreme 128GB Pro drive. The SanDisk Extreme 128GB may show slightly different timings to the SanDisk Extreme 64GB.

P.S. The drive case for the Extreme Pro was slightly larger than the Extreme and was half-metal. Personally, I did not feel it to be of particularly good quality, or very attractive or very tactile - so the metal case was not really a plus-point for me.

See also: my previous blog post on the Lexar P20 and why you shouldn't buy it!

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