Wednesday , 23 April 2014
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ASUS Zenbook SSD Review – Not Necessarily SandForce Driven Hits A Speed Bump

If we told you that we spent $2400 to right a wrong in proving something that you as a consumer should be aware of, would you believe us?

This report closely examines the ASUS Zenbook.  Within the ‘Zen’, ASUS may provide either of two SATA 3 SSDs, these being the AData ‘SandForce Driven’ XM11 or the Sandisk U100. There is no price difference between the two, the product number is the same and the consumer has no way of knowing which they will receive.

The performance drop between the two is significant.  Our concern, in fact, led to our investing  in one of each Zenbook (AData/Sandisk), and then voiding the warranties to confirm SSD configuration, so that potential buyers have  a clear view of this.  We believe ASUS should be clearly identifying the SSD on exterior packaging and within specifications just as they would a CPU, especially since the SSD is responsible for the largest visible upgrade we see in computer performance today.


We will be the first to concede that we are not the first to explore this topic as AnandTech covered it some time ago in their Asus Zenbook UX21 Review quite well and we had since received a few e-mails from unhappy customers whom had unknowingly received a system containing the SSD that was not of their choice.  It seems there was no way of identifying the SSD on the exterior packaging and the first signs of SSD identification were found on the interior box which would be seen after purchase.

In fact, it wasn’t until our review of the Samsung PM830 SATA 3 SSD that we had even considered the viability of a Zenbook purchase, this being the result of an unhappy reader asking why we weren’t testing a SATA 3 mSATA SSD in a system for which it was intended, rather than on our Test Bench.  He was absolutely right.

Our next stop was deep within the pages of several tech site reviews where we found a large number of AData XM11 included Zenbooks with great performance results, but we could not find a review with the Sandisk U100 SATA 3 SSD.  We found it odd as the performance detailed by ASUS did match that of the included ‘SandForce Driven’ SSD but what about the Sandisk U100?  It was there that we found some rather remarkable user posts (1,2,3) that opened up our eyes to something that we feel should be rectified by ASUS.


Given this information, we decided to visit three major chain retailers and do a bit of ‘benchmarking on the go’ where we were very surprised that two of the chains no longer had the Zenbook on display, however, we were free to order online and would receive the product in a few days.  That didn’t work as we leave for CEBit in beautiful Hanover, Germany in a short twenty one hours from now.  We hit the third at which time the conscious decision was made to purchase one of each system.  The deciding factor came from information learned that the Windows Experience Index for the Sandisk U100 was only 5.9, whereas it was significantly higher at 7.9 for the AData XM11.

Our end purchase consisted of a ASUS Zenbook UX21 with a AData 120GB SATA 3 SSD installed and a UX31 with the Sandisk U100 SSD installed.  As much as some may believe that the configurations should be exact, the simple fact is that we are only testing the SSD of the system and both are Sandy Bridge systems capable of amazing SATA 3 speeds after all.  We simply have no use for two exact laptops at the office.

As a bit of a side note, those familiar with SSDs are aware that ‘SandForce Driven’ SSDs such as the AData XM11 are of the 120GB capacity while the Sandisk U100 SSD is 128GB, yet both of our packages identified the internal SSD as 128GB.  Given the value of SSD real estate, that loss of 8GB on a system advertised as 128GB is just a bit deceiving.


These pictures display the SSDs as they were being removed from the chassis.  It is not a simple task as the chassis is secured by several very small torx screws and the SSD screw is covered by security tape which meant that removal voided the warranties.


About Les Tokar

is a technology nut and Founder of The SSD Review. His early work includes the first consumer SSD review along with MS Vista, Win 7 and SSD Optimization Guides. Les is fortunate to, not only evaluate and provide opinion on consumer and enterprise solid state storage but also, travel the world in search of new technologies and great friendships. Google+
  • John

    I have the Sandisk SSD. Could this be the reason my Zenbook 31a freezes and stutters when compressing large files or using bittorrent on a 100 mbit connection? It has been a real disappointment as my old Asus Eeebox 1501p with a 5400 SATA II drive and 1.8 GHz dual core atom felt a lot smoother.

    Might there be another more serious hardware problem or is this acceptable when buying an expensive state of the art ultrabook? Im considering trying to get it exchanged at my retailer but I dont want to be without my main computer for whatever time it takes if they are just gonna wipe my install and then return it.

    • Les@TheSSDReview

      I have heard same from others and that could be attributed directly to that SSD.

  • jkosonen

    My asus zenbook crashed, is there a way to get data out of the ssd. I don’t seem to find any sata adapter to work with this ssd card. Any ideas how to get the data out?

  • mindteaser

    Are you aware of any issues in the Asus Zenbook with the 256GB SSDs? I was looking at the UX31A-DH71 which comes with a 256GB SSD. I read somewhere that you may be able to tell what SSD is installed by the serial number of the laptop (that’s on the outside of the box).

    • Les@TheSSDReview

      You can tell if you can get to the inside box and, as well, if you get to the system itself. If it is a 256GB, it limits the possibilities as I have not seen a SF controlled SSD in a pre-built system with 256GB, although it is possible.

  • wingmasterx

    UX31A-BHIT11 (touch screen) has a much better SanDisk drive now than previous UX31A models. I purchased this computer from BestBuy today, and was at first disappointed to find the dreaded SanDisk logo on the inner box. However, I ran some of the benchmarks used here, and my drive has better performance than ADATA XM11! I have included a summary of my test results below vs. scores reported for XM11 in this article.

    My drive is: SanDisk SD5SE2128G1002E.

    Windows Experience Index (disk data transfer rate) : 8.1 SanDisk vs. 7.9 XM11
    AS SSD Benchmark (total score): 750 SanDisk vs. 465 XM11
    AS SSD Benchmark (Acc.Time Read / Write): 0.157ms / 0.096ms SanDisk vs. 0.145ms / 0.331ms XM11

    My drive also performed favorably on the CrystalDiskMark test (though I neglect to list the actual numbers)

    • Les@TheSSDReview

      Those arent really fair reflections of that drive and I was curious as to high sequential reads and writes, along with the low 4k writes, even wthout comparison. Can you send those along?

      • wingmasterx

        Here are my CyrstalDiskMark 3.0.2 x64 tests using settings for default random data and (x5, 1000MB):

        Read [MB/s] Write[MB/s]
        Seq 491.2 335.9
        512K 290.5 345.5
        4K 21.79 41.33
        4K QD32 257.9 179.0

        Is this what you wanted? If not I can report something else if you can point me in the direction.

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