SCSI controller comparison

[darksun9210]

cyberstormPPC/060
ultrawide scsi seagate 18Gb with a 2/4KB block size, i got around 22MB/s. i dare say even faster with more modern drives.

A4000T/warpengine040scsi/Cyberstorm2-040scsi
scsi quantum fireball 9.1Gb with 2KB block size, i got just over 7Mb/s in async, and nearly 10MB/s in Sync mode.
i guess this counts for the A4091 and fastlane aswell as they use the same chip, but i've never owned an A4091 or fastlane so can't confirm.

A3000 i've never owned,

A2091 in an A4000, its best to have some ram onboard for the scsi chip to DMA into, there is a patch on aminet for this, but then you are limited to the Zorro2 interface at around 2+MB/s
without the onboard ram and the patch, an A2091 in an A4000 gets about 150-200KB/s in my expirience.
A2091 in an A2000, can dump into zorro2 ram anywhere, but again the zorro2 interface is the limit.
The GVP HD8+ is again limited by the zorro2 interface, but doesn't have the DMA issues the A2091 has in an A4000.

The blizzardIV030/040/060 scsi can happily manage 10MB/s as can the blizzardPPC scsi, as these are direct DMA devices on the processor bus.

basic rule of thumb. the more modern the drive, the better.

i hope this helps.  :-)

[darksun9210]

cheers matey  :-)

oooh, i forgot, there is a FAAAAAAST rom upgrade available for GVP scsi controllers covering GVP's HD8+ series for A500/zorro2

basicly from what i can understand, it enables longword DMA transfers over the Zorro2 bus. you need some fast ram in the zorro2 address range, but it can squeeze out nearly 3.6MB/s!  :-o
i dunno, sounds like witchcraft to me :-D

[darksun9210]

no idea how fast, but you can get it from here:-

software hut W.D. scsi chip rev8

hope this helps :-)