CSPPC and Mixing UltraWide and Fast Scsi Devices

[Reflex]

Hello,

I have a quite expanded Amiga 4000 with a PPC and a lot of drives.

Here there is my chain:

- Termination
- Controller
- Quantum Atlas 9GB HD
- Fujitsu 76GB HD
- Acard 7730A with 120GB Sata SSD
- 68=> 50 pin adapter wit upper bites termination
- Iomega ZIP 100
- Iomega JAZ 2GB
- Sony 40X CD-ROM
- Yamaha 4x4x16 CD-Burner

The hard drive will be unmounted as soon as I copy everything on the SATA hard drive, i bought it as the other hard drives are way too noisy.

Anyway I read somewhere that mixing UW devices with SCSI-2 ones will slow down the whole chain to 10 mb/s speed, but this doesn't happen with UltraScsi ones.

But How can i understand what of my devices are SCSI-2, Fast Scsi or Ultra SCSI?

I guess that the iomega Jaz is an Ultra Scsi device but what about all the other ones?

Moreover will a Fast SCSI device slow down the whole chain too?

Any suggestion/advice is welcome.

[Reflex]

In real life I never got better performance than 20Mbytes/sec or so anyway even off a nice 15Krpm Ultra320 drive running in Ultra160 mode. The 68060 became the limiting factor in how fast the OS could service the DMA buffers. Running AmigaOS 4.1 might give more of a benefit.

I used Unit control, tried to switch all the devices to Synchronous mode and it worked for all but the Zip-100 one.
Indeed this one cannot be switched to Syncronous mode at all neither selecthin this on the early startup menu...

As it's a slow drive I'm considering to take an IDE one.

Anyway can you suggest me a reliable speed benchmark? I use SCSIbench and DiskMonTools but they both don't seem to be very realiable.