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Honor Student
Posts: 2
Member Since: ‎01-15-2014
Message 1 of 3 (1,311 Views)

add AHCI mode on a Z820


I bought an  individual configured Z820 1 1/2 years ago from a german reseller. Now I wanted to add an additional SSD to it as a Scratch Disk (I work in the movie business and we have a lot of data that is needed only for a short amount of time; this disk is meant for those data)

After the installation was completed and the system saw the disk I tried different Benchmarktests ( AS Bench, ATTO Bench and Samsung Magician; which also has a Benchmark Option). What really surprised me that 2 out of 3  showed really low write values (only ATTO Bench delieverd high values while reading and writting). I also noted that the AHCI option was turned off. On the internet you can read that AHCI is vital/necessary for SSDs to work properly and so that it lives longer.
I also read that you can turn this option on afterwards (changing a setting in the registry as well as in the BIOS).


Now I wanted to know if this is really necessary and if changing it can cause serious problems with my Z820 (especially with my Raid 1)? I asked some others and those said I should leave it as is but I'm not sure anymore.

I use Win7 prof and my OS is on a SSD (Samsung 830). In addition I have 2 HDDs for my media and projects configured as RAID 1. And for the last 5 days a new SSD (Samsung 840 pro) as mentioned for use as a Scratch Disk.


Thanks for your help.

0 Kudos
Posts: 118
Member Since: ‎12-01-2008
Message 2 of 3 (1,303 Views)

Re: add AHCI mode on a Z820

Just curious - you said you have RAID 1 configured. If your SATA emulation in BIOS is not set to RAID/AHCI, you can't really do hardware RAID.


The registry tweak works for changing from IDE to AHCI, and it surely adds performance. But if your SATA emulation is already in RAID mode, you don't have to change anything.


How are your disks connected? The Z820 has 2 x 6Gbps SATA ports + 4 x 3Gbps SATA ports. The 6Gbps SATA ports are colored differently then the 3Gbps ports. Apart from these, you also have 8 x 6Gbps SAS ports.


You may want to try moving the new SSD to a SAS port and rerun the benchmarks to see if it improves. Also, please check the BIOS, and in Storage Options, see what is the SATA emulation.



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Grad Student
Posts: 221
Member Since: ‎04-12-2011
Message 3 of 3 (1,290 Views)

Re: add AHCI mode on a Z820

If you change the storage mode to AHCI mode from RAID mode, youhave to reinstall the OS to work with the AHCI mode. I'm not sure if the AHCI mode willenahce the low writing performance.


Going back to your original issue "low writing performance", what did you conclude the systmem has the low writing performance? Due to low value? What are all three values? Did you test with the different settings such as different size and number of buffers? What is the hardware configuration? Did you connect your ssd drives to ahci 3Gb/s , ahci 6Gb/s, SCU, or SAS ports? What storage driver was insalled? There are too many variables to be considered.

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