XVI 16mhz mode and Geograph Seal crash

[trixster]

Hi,

I have an XVI with 2MB PIO-6834-2/4M-1 ram board (jumpers set to 0 0 0 0) which works great in all respects except with Geograph Seal.

With the XVI set to 16Mhz I cannot get GS to run with switch.x set to 4096KB, either running from SCSI2SD or from floppy disks. I always get a Bus Error or Address Error once trying to start from the game menu.

If I set the machine to 10Mhz then the game plays fine either from scsi2sd or floppies with switch.x at 4096KB.

But if I set switch.x to 2048KB I can then successfully play the game at both 16 and 10Mhz.

So what is it about 16Mhz and my ram expansion that GS does not like?

I have run MTEST to confirm the memory on the PIO is fine, and in all other respects the machine operates great at 16Mhz....

[SuperDeadite]

Geograph is one of the very few games that takes full advantage of the XVI's faster internal RAM.  The i/o slots are slower.  You need to use the mobo's internal RAM expansion for geograph to function properly at 16mhz.  99% of the library does not care about the speed issue though.

[trixster]

Thanks for the info, that's interesting. I guess I'll need to check yahoo jp for an internal memory upgrade then.