Blackmagic Forum

Hi everyone,

I notice a couple of months ago my raid started to slow down the write speed. i thought it was because of how I use it. The normal speed is around W1000 and R1000. The write goes down to 650.

I did a test. Turn the mac on, speed test W 1000. Open all apps I use except resolve. All good Write still 1000. Open Resolve project screen still good. Open 1 project goes down to 650. The more interest thing is. Ok lets close resolve and test it again. Write still 650.

How is that possible and why is it doing that?

Thanks.

mac pro 6core 64RAM D700 1TB
Davinci Resolve 15 beta. It happen on 14 as well.
Raid Areca 8050T2 32TB
Blackmagic speed test

Are you reading and writing from the same drive? Or are these just disk sped test results?


Sent from my iPhone using Tapatalk Pro

These are just speed results.

I also turned it off the automatic caching and background caching.

SOLVED

You can not put a ultrastudio on the same thunderbolt bus as your RAID. The OS allocate a portion of the bandwidth for the ultrastudio. So when I opened the davinci resolve I started using the ultrastudio but even after closing resolve or when not using the ultrastudio the OS would still keep the bandwidth allocation.

So the answer is use another BUS!

Yeah i also only recently discovered this when i added a 10G adapter on my thunderbolt 2 chain that also had a mini monitor and a small raid. Individualy all good but when network was used raid slowed and when mini mon was used net was slow down etc etc etc. Turned out my 2 separate TB ports where on the same internal TB bus so....
Needed to reshuffle the lot and moved RAID off TB to just SATA drives with softraid as no more free PCIE slots for other types of solutions
But its all sort of working now with some minor limitations.