Pegasus32 R6 - 1000mb/s les Read speed then Write

  • Last Post 20 December 2022
Dinu Petrache posted this 19 November 2022

Hi there community!

I just enjoy my new Pegasus32 on Raid5 (24TB) and I discovered doing some tests that Read speed, who should be much faster then write speed, are so much slower. I really appreciate all of you any kind of information about this. Im not expert but having almost 2000mb/s write and 700mb/s read, it's quite strange for me guys...


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Dinu Petrache posted this 20 November 2022

Hey guys, nobody?

Babatunde Akinkuolie posted this 20 November 2022


Kindly register the unit using the serial number by logging into and open a web support ticket with the service report of the unit attached so we could check further.

Steps to save the subsystem 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.

Dinu Petrache posted this 18 December 2022

Well my friend I did it and nothing happen since 7 weeks ago... Talking and talking but no clear information about my case. Its look like that form them this is normal situation and I was trying to find if there is anybody else with the same problem. I dont understant how could be normal situation because all my other extrnal drives from other Companies have diferent behavier... I do not find customers on youtube with Ride5 testing the unit or Promise to give me an exemple. They advice me to backup the unit and reset it - but backup where? I bought this unit for backup not for backup backup....

I hope to find someone around here to give me a hand.

R P posted this 19 December 2022

Hi Dinu,

It is not possible to debug any issue with no information. If you take your car to the shop saying it's broken, they won't even know what to look at and probably won't accept the car.

The issue here is system performance, not Pegaus performance per se. In one case it was discovered that anti-virus software was causing performance degradation as it checked every file read or written for viruses. The Pegasus was working as expected. And given that your write speeds are good, it seems likely that your Pegasus is working OK.

That being said, if you upload a service report here we can at least take a look at the Pegasus.

Dinu Petrache posted this 19 December 2022

I understand. I do not habe antivirus, just in case, and I would try to upload my report service here but I dont know how. Thanks for try to help...

Dinu Petrache posted this 19 December 2022

Dinu Petrache posted this 19 December 2022

I fond a way...

R P posted this 19 December 2022

Hi Dinu,

In your first post you uploaded an image.

A few comments below are instructions for generating a service report.

I would suggest zipping the service report, then upload it the same way you uploaded the screenshot.

Dinu Petrache posted this 19 December 2022

Ok sorry, i just fond it

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R P posted this 19 December 2022

Hi Dinu,

It was not necessary to upload it as your link worked just fine.

But looking at the service report I don't see anything wrong with the Pegasus. The drive's SMART data shows that all the drives are in good shape. The Pegasus firmware is the latest version. Everything looks good on the Pegasus.

So let's try changing something. The driver is probably the only option here.

So the suggestion is to...

1. Uninstall the DEXT driver (there is an uninstall option in finder in Applications).

2. Install the kernel space driver.

Please read the install PDF in the driver package, you'll have to make a change to the OS security level. Then you'll have to give the driver permission to run in Settings > Security.

Dinu Petrache posted this 19 December 2022

Ok I will try but 2 issues first:

1 - before iinstalling the DEXT I had the same speed

2 - last week when I was trying to uninstall the DEXT my Pegasus partition was literally GONE out nowhere. I did iinstall the DEXT and "wake" up on my  system!

R P posted this 19 December 2022

Hi Dinu,

If you had the kext previously installed and then installed the DEXT and nothing changed, then don't bother going back to the kext.

last week when I was trying to uninstall the DEXT my Pegasus partition was literally GONE out nowhere

If you have no driver insatlled you won't be able to see the Pegasus volume.

When you install the DEXT, the installer deletes the kext. So if you delete the DEXT you need to reinstall the kext before your volume will be visible. Of course reinstalling the DEXT will also bring the volume back online.

Do you have much data on the disk? If you can move whatever data you have elsewhere I have an idea. We can test each disk individually and test their read speeds. A RAID is no faster than it's slowest disk.


Dinu Petrache posted this 20 December 2022

I did all you said but the same speed

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Dinu Petrache posted this 20 December 2022

About move my data elsewhere - I bought pegasus to move my entire data to my unit, now its imposible to move it back. Few others external ssd are gone (sale)... Why you asking me its impossible right now. With its strange for me its - for real, nobody have R6 on Ride5 to share me if has the same experience? Not even Promise inside the factory? Just a simple test - same like I did - check the unit, check the driver, check the speed - and done...

Maybe we are able to find someone...

Thanks again

R P posted this 20 December 2022

Hi Dinu,

I just checked 2 Pegasus R6 units in my lab. My Black Magic settings may be different from yours. These were run on an M1 MAC mini.

These results are from the Pegasus 2 R6 which was already attached through a TB2 > TB3 converter.

Most likely 830 MB/s is about the bandwidth limit of Thunderbolt 2.

These reaults are from a Pegasus32 R6 connected by Thunderbolt 3.

My write speeds are slower than yours but the read speed is about the same.

The thing about writes is that they are cached, that is the writes are saved to cache memory rather than being written straight to disk. Reads come straight from the disk. This means that often write speeds are faster than read speeds depending on how things are implimented and what kind of IO is being run. But read speeds being slower is not unexpected or a sign of a problem.

But with spinning disks (which you have) your results look good.

Dinu Petrache posted this 20 December 2022

Do not forget that my unit its v3 Pegasus 3 R6

R P posted this 20 December 2022

Hi Dinu,

Your service report says it's a Pegasus32.

[Subsys info]

Alias: Pegasus32 R6
Vendor: Promise Technology,Inc.        Model: Pegasus32 R6
PartNo: F29C1R620000000                SerialNo: XBXXXXXXXXX
Rev: B1                                WWN: 2000-0001-5564-4bf0
CBSN: MD3L22615500169                  Interface: Thunderbolt 3


Dinu Petrache posted this 20 December 2022

I was aspecting different kind of speed. Before to buy the unit I was watching this video 

and cleary the speed are huge diference between your publicity and reallity.

Dinu Petrache posted this 20 December 2022

I think that more videos with all Raid configuration and much more presentation (video presentation) would be better for your future clients. I do not understand at this level why its so hard to find something like this on your website? Just consider it that a simple vst library that cost around $50 has between 3-5 video tutorials with specific details about the library. Your units cost more then a VW Golf bro (more expensive that a used car) mine cost me more than 2000 Euro and im not able to find video tutorials about all I need on your website? That kind of short video its almost nothing compare with what we really need. All this conversations you can avoid with specific presentations and reviews about Pegasus32 on your website... 

R P posted this 20 December 2022

 Hi Dinu,

The video makes it clear that the display Pegasus32 R8 has SSDs rather than spinning disks.

We have a Pegasus32 R4 in the lab with (4) 2TB SSDs and it gets about 2000 MB/s reads and writes.

The thing about SSDs is that they are expensive, especially the larger SSDs which would be needed for video production.

Regarding videos, specifically what kind of videos are you looking for?