I am upgrading my z800 to a z840.
I use the builtin external SAS port to connect to an Avid VideoRAID SR external RAID. This is a hardware raid, that presents itself as a single disk to the system.
It worked great on my z800 running windows 7. I got read/write speeds of 400-500MB/s. I plugged it into my new z840 (also on the external back panel SAS) - and the drive shows up fine, but im getting absymal speeds. It starts are like 100MB/s but then quickly drops down to 20 or 30 - making it essentially unusable.
Is there some configuration I'm missing here?