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[amiga1260]

I want to buy a CPU 68030@50 MHz and a 68882@50 MHz from Softhut to replace the 68030EC @ 40 Mhz.


Do I only need a crystal of 50 Mhz, to get them both running at 50 Mhz?

[amigadave]

Check your current crystal for the 40mHz 68030. If it is 80mhz, then you need a 100mHz crystal for the 50mHz 68030 CPU and 68882 FPU you are installing.

I have the same accelerator for sale and when I return home in a couple of days, I could check what is installed in mine.

[rkauer]

Yes, just one crystal.

[amiga1260]

@Amigadave: The crystal of my GVP board is a 40 Mhz crystal.

[amigadave]

amiga1260 wrote:
@Amigadave: The crystal of my GVP board is a 40 Mhz crystal.

Then you know you only need a 50Mhz crystal for your proposed upgrade. I have noticed on some other accelerator cards that the crystals are twice the CPU and/or FPU speed and the circuitry must halve the clock for them. As I am away from home, I could not check my GVP 1230 Turbo+ Series II to see what it used.

Good luck with your upgrade. If it does not run correctly at the faster speed, you could always re-install the 40Mhz crystal, but retain the 50Mhz CPU to have the full MMU.

[countzero]

amigadave wrote:
I have noticed on some other accelerator cards that the crystals are twice the CPU and/or FPU speed and the circuitry must halve the clock for them.

you're talking about 68040 boards. 68030 uses 1/1 clock. (also 68060)