A4000 and A4091

[marmotta]

It's been a while, but I recall performance for reads was 4-5 MB/s (the same setup on my TekMagic 2060 was about 9 MB/s, measured with RSCP). Filesystem benchmarks were the same as accelerators I've tested with onboard SCSI, so in practice (booting, opening windows, etc) it feels really zippy. It also works flawless copying to and from drives on my DENEB (funny, considering it crashes when copying between two drives on the DENEB, but that's another story...).

You have the A4091, true? You can confirm my boot-up steps?

If I power-on my Amiga it load wb from scsi without a problem, if I reset... no problem. If I go to boot menu (left+right mouse button) and continue the boot process (with or without startup-sequence) my Amiga go to the kickstart screen! I need to reset for load a wb. Is a normal?

[marmotta]

You may of seen this:
http://www.hough.ca/personal/4091.html#a3640
An interesting note here about how rev 3.1 A3640 needs u209 to be -03(aka like on rev3.2) or there are DMA problems supposedly.I never noticed this way back when i had a 4091.
not sure if this would impact speed.
At the end of the day a quality accelerator with scsi onboard is always best

My U209 is -02

But in this link say the 02 is correct: http://vintagecomputercafe.com/amiga/A4091%20ROM.txt

[marmotta]

I changed all capacitors on the A4091 but the problem is not solved...

[marmotta]

I think you are getting all you can from that combo. If you want faster scsi i would suggest a good accelerator with scsi(not apollo).
Cyberstorm MK3/ppc will get you UWscsi at around 30-40MB/s.
warp engine, cyberstorm MKII,gvp4060DT,etc around 9-10MB/s

The problem is not the speed, I not found why if I go in the boot menu I see the kickstart screen... Only I have this problem?

[marmotta]

The A4091 doesn't need rev 3.2 A3640, 3.1 should work just fine.  Also the problem is the Motherboard RAM/A3640, it was designed for the A3000 so the crippled A4000 Motherboard memory with the A3640 is at fault for the 4-5MB/s speeds.  Remember to set Synchronous mode in the RDB and if possible get some Z3 RAM.  With an 3128 or something like it with higher priority than motherboard memory you can get 7MB/s.  But since the 3128 is slower still than A4000 motherboard RAM for CPU access the rest of your system slows down slightly.

And for boot problem? Why if I enter in the early startup menu and I press boot or boot without startup-sequence I have the kickstart screen? When I reset the hdd load without problems...

[marmotta]

To me this opens the question..

How do you use the early boot screen correctly?
Since the Early start menu shows all devices, do you have to select?
Are the different part bootable? the same priority numbers?
Do you have to enable/disable?

In the early startup menu I have my partitions (dh0, dh1) at device scsi-1, all is enabled and I can select the dh1 (workbench bootable). When I press boot appears the screen of floppy fly in to the drive... I reset, all ok..  is very strange!

[marmotta]

It could be your drive is taking too long to spin-up.  Try flipping dipswitch 5, this gives it more time to spin the drive up.

DIP switch settings        
switch 1-3- SCSI ID        
switch 4- fast bus: ON - disabled        
switch 5- delayed autoboot: ON - enabled        
switch 6- synchronous mode: ON - disabled        
switch 7- termination: ON - disabled        
switch 8- LUN: ON - enabled

When I click on "boot" the hdd is alredy spin and initialized... delay not help

If we are confirm is not a normal for a4091... I suspect a hardware problem but I can't found it

[marmotta]

I don't think it's a hardware problem.  Could you post your system specs again currently?  Are you using Aztec Monster, are there any IDE devices?  Did you try PFS-AIO?

I have tried some configurations, my A4000 is recapped, a3640 is v3.1, buster 11 and 3.1 rom (original not flashed).

I not use Ide devices

[marmotta]

Have you tried with the dipswitch 7 termination off?

Yes I have external active terminator

[marmotta]

And an internal one?

Yes, the original active terminator of A4091