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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Flashlab on November 06, 2005, 08:59:02 PM

Title: A4000 ROM Speed jumper
Post by: Flashlab on November 06, 2005, 08:59:02 PM

On the A4000 motherboard there is a jumper for ROM Speed. It can be set to 160 or 200 ns. Default is 200 ns.

I guess faster is better and then you want 160 ns. Or is this unstable?

Title: Re: A4000 ROM Speed jumper
Post by: Flashlab on November 07, 2005, 05:48:33 PM

 :bump:

Title: Re: A4000 ROM Speed jumper
Post by: Zac67 on November 07, 2005, 06:09:31 PM

Depends on how fast the ROMs fitted actually are... -20 is 200ns, -12 is 120ns and so on.

Title: Re: A4000 ROM Speed jumper
Post by: Tigger on November 07, 2005, 06:16:12 PM

Unless you are putting new ROMs in I would leave it where it was, in actuality, even if you have 160's in your computer, its not enough difference for you to really notice.
   -Tig

Title: Re: A4000 ROM Speed jumper
Post by: alenppc on November 07, 2005, 07:51:08 PM

I quote:

"If you move the J151 jumper from position 1-2 to 2-3 without first installing faster ROM chips, you will get an average system speed increase equal to 0.5% while the system error rate will go up by about 40%."

Title: Re: A4000 ROM Speed jumper
Post by: patrik on November 07, 2005, 07:51:36 PM

@Flashlab:

If you want a speedy rom then dont use it. That might sound wierd, but there are utilities that copies the rom to ram and makes to amiga access it from there. As long as that ram isnt chip-ram or some shoddy 16-bit fastram it will be faster than the rom. For example the cpu command supplied with Workbench can do this by using the mmu if you supply the parameter "fastrom".


/Patrik

Title: Re: A4000 ROM Speed jumper
Post by: Flashlab on November 07, 2005, 09:23:17 PM

Ok so a tool like Blizkick is what is needed. I have compatible boards so I'll look at those.