Pegasus32 R6 24TB Slow speed

  • Last Post 12 March 2022
M Wilson posted this 03 July 2020

My Pegasus32 R6 24TB RAID 5 is connected to a 2019 MacBook Pro (16,1) with the supplied Thunderbolt 3 cable. Blackmagic speed test shows inconsistent results.

When testing with a 5GB  file, the write speed is 149.5 MB/s and 551.3 MB/s read.  

These numbers will remain low for a few read/write cycles. Then the write speed will ramp up to over 1500 MB/s for a second and then settle at about 641.9 MB/s write and 428.5 MB/s read.  

When using an Apple USB C to USB A  adapter and suitable USB A - USB C cable (Effectively USB-C to USB-C cable connecting Mac and Pegasus) I get a smooth and consistent 865 MB/s write and 778 MB/s Read

I am able to repeate this test consistently with different thunderbolt 3 cables before and after installing the macOS 6.2.13 driver (which is already imbeded in the OS?). I tried all ports on the MacBook Pro and both Thunderbolt ports on the RAID. The AJA system test lite produces similar results. 

The Promise Utility 4.04  NVRAM and Runtime Events shows only normal start and stop events.  

Is this normal performance?  If not, what performance should I expect?


macOS 10.15.5

Pegasus32 R6

6.2.13 Driver





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Raghuraman Kannan posted this 06 July 2020


Please do register yourself as a user at and open a case with the report.

Steps to save the report:

1) Open Promise Utility.

2) Click subsystem information icon on the top of the window.

3) Click the lock symbol on the left bottom corner of the screen to unlock the utility.

4) Click on save service report button to save the subsystem report and attach it to the case.

Thanks !

M Wilson posted this 12 August 2020

I opened a case on July 6th 2020, provided requested details, followed up twice, but have not received any response from Promise Support about this case. 


Ranjith kumar posted this 13 August 2020

Hi Wilson,

Sorry for the inconvenience caused to you,

Could you attach the latest subsystem report in that case id.

Thank you,



M Wilson posted this 13 August 2020


Nothing has changed on the computer nor RAID. The subsystem report is the same. 

I am waiting for an update or solution before putting the equipment into production.

Are the performance numbers I described expected?  If not, is there a remedy? 


M Wilson posted this 12 March 2022

There has been no resolution to this problem.

Any updates?