Types not listed above has to be verified.

Windows 10 x64

Windows 10 x64 hardware installation package is created. One generic installation package cover all of the hardware configurations models listed above.

Windows 7 x64

A new and revised Windows 7 x64 hardware installation package is created for the Lenovo ThinkCentre M900. One generic installation package cover all of the hardware configurations models listed above.

Defective hardware design generates weak disk access results

There is mainly two significant different configurations:
One with a NVMe controller (Non-Volatile Memory express), and the other that use a SATA controller.

Disk access is normally the PCs major bottleneck, so a NVMe “disk controller” should normally be an appreciated approvement.

We have run disk performance tests on these two disk controller options on PCs with Windows 7 and Windows 10 (x64) installed.
The SATA based model performs well under all conditions. They are all setup with SSD (Solid State Disk) storage.
The NVMe based model is more of a disappointment.

There seems to be a problem with the NVMe model. When the storage thermal sensor passes an upper thermal limit of about 77 ^∘ C, the storage chip reduces the read and write speed significantly. This is to protect storage hardware from overheating. To achieve the high transfer speed again, the temperature has to be reduces to below at least 70 ^∘ C. This does not always happen under normal circumstances. It also depends on room temperature.

This storage throttling could probably have been avoided if Lenovo had used a heat sink on the storage chip, and/or a better ventilation inside the M900. Now the storage chip is squeezed in with no possibility to "breathe" and remove the heat.

"Hot" NVMe controller performance

    Sequential Read :   577.960 MB/s
   Sequential Write :    35.632 MB/s
   Random Read 4KiB :    33.004 MB/s [  8057.6 IOPS]
  Random Write 4KiB :    35.189 MB/s [  8591.1 IOPS]
    Sequential Read :    32.933 MB/s
   Sequential Write :    35.450 MB/s
   Random Read 4KiB :    16.980 MB/s [  4145.5 IOPS]
  Random Write 4KiB :    34.619 MB/s [  8451.9 IOPS]

"Cool" NVMe controller performance

    Sequential Read :  1812.100 MB/s
   Sequential Write :   594.936 MB/s
   Random Read 4KiB :   908.116 MB/s [221708.0 IOPS]
  Random Write 4KiB :   590.051 MB/s [144055.4 IOPS]
    Sequential Read :   534.651 MB/s
   Sequential Write :    35.658 MB/s
   Random Read 4KiB :    42.173 MB/s [ 10296.1 IOPS]
  Random Write 4KiB :   258.770 MB/s [ 63176.3 IOPS]

SATA controller performance

    Sequential Read :   526.446 MB/s
   Sequential Write :   457.850 MB/s
   Random Read 4KiB :   337.425 MB/s [ 82379.2 IOPS]
  Random Write 4KiB :   230.021 MB/s [ 56157.5 IOPS]
    Sequential Read :   491.082 MB/s
   Sequential Write :   433.967 MB/s
   Random Read 4KiB :    35.219 MB/s [  8598.4 IOPS]
  Random Write 4KiB :   136.698 MB/s [ 33373.5 IOPS]

This problem could only be fixed by Lenovo.

Final word:

If you go for the NVMe model, be sure to place the PC where the "air-condition" is good. Don't cover the PC but let it "breath".
My personal recommendation would be to go for the SATA model if heavy duty disk access is not essential.
A M900 with a bigger PC casing could be a better alternative, but we actually don’t know.

In the next release of this modell, Lenovo should ensure that the SSD is sufficiently cooled.