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Optane 900P with AHCI or Intel RST in BIOS?


I'm using the PCIe slot card version of the Optane 900P as the OS and boot drive and two conventional hard drives for storage (not in RAID config), with a 8700k and an Asus Rog Maximus X Hero motherboard.

In the bios, I have two options for SATA Mode selection :


- Intel RST Premium With Intel Optane System Acceleration (RAID)

Is there any performance difference between the two? When I installed the OS (Win 10) it was set up on default setting AHCI, could I still switch to RST if that offers tangible performance benefits, or would I have to wipe the Optane and install Windows anew?

I've noticed that the diagramm-as-ssd-benchmark-4k-64thrd Computerbase Benchmark with AS SSD produces a vastly better performance for 4k-64Thrd read score:

This is how my Optane does in comparison:

Strangely, the write score is better on my Optane, but overall score is still significantly lower. Of course the Computerbase benchmark did bench the Optane as a secondary drive, not as the OS drive, so that might figure in.

The other benchmark graphic of the AS SSD benchmark mentions "Ram Caching!", so I assume that has something to do with the vastly improved read performance? How do I enable that - or should I? What are the benefits?

Another AS SSD benchmark on SSD Reviews shows a benchmark very similar to mine, just a tad bit faster in every score though:

Finally, the Computerbase CrystalDiskMark score on the empty Optane

performs better in every category, but way worse than mine in 4KiB Q8T8.


CrystalDiskMark 6.0.0 x64 (C) 2007-2017 hiyohiyo

Crystal Dew World :


* 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) : 2684.577 MB/s

Sequential Write (Q= 32,T= 1) : 2258.161 MB/s

Random Read 4KiB (Q= 8,T= 8) : 2347.825 MB/s [ 573199.5 IOPS]

Random Write 4KiB (Q= 8,T= 8) : 2214.870 MB/s [ 540739.7 IOPS]

Random Read 4KiB (Q= 32,T= 1) : 682.370 MB/s [ 166594.2 IOPS]

Random Write 4KiB (Q= 32,T= 1) : 616.936 MB/s [ 150619.1 IOPS]

Random Read 4KiB (Q= 1,T= 1) : 277.560 MB/s [ 67763.7 IOPS]

Random Write 4KiB (Q= 1,T= 1) : 241.043 MB/s [ 58848.4 IOPS]

Test : 1024 MiB [C: 8.8% (39.1/446.5 GiB)] (x3) [Interval=5 sec]

Date : 2018/01/04 2:16:25

OS : Windows 10 Professional [10.0 Build 16299] (x64)

Bottom line: Did I miss a setting to improve performance in either BIOS or Win10? Can - and should I switch from AHCI to RST in the Bios, given that I use the 900P as a systems drive and two hdds not in raid as storage?

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2 Replies

Hello VoxPopulist,

Thanks for posting in our community.

There are no performance differences between AHCI and Intel RST Premium With Intel Optane System Acceleration ( simply referred as RAID on older motherboards) modes. As the name suggests, RAID mode is used if you want to set a RAID volume using Intel® Rapid Storage Technologies (Intel® RST). Usually, and OS reinstallation is required when changing modes.

As for the benchmarks from the site you shared, they say the following about 4K-64Thrd: "This has nothing to do with the performance of the SSD. The values are therefore not included in the overall ranking." , meaning these results should't be considered for performance.

Please refer to the official Performance information on the product specification site, focusing on the sequential write/read results:

- Intel® Optane™ SSD 900P Series Product Specification

Based on this, your drive shows excellent performance in both AS SSD Benchmark* and CrystalDiskMark*. We don't recommend changing any settings as it is. However, there's an evaluation guide available with recommendations to obtain better results for benchmarking if you want to check it:

- Intel® Optane™ SSD 900P Series Evaluation Guide

I hope this information will be useful for you. Please let us know if there's anything else we can help you with.

Best regards,


Eugenio F.
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Hello VoxPopulist,



We haven't heard from you since the creation of the post. Please let us know if there's anything else we can help you with.



Best regards,


Eugenio F.
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