@Karlos
Maybe the DMA is disabled but still appears to work. The PCI CFGCommand register (offset 0x04 from configuration base) has several configuration bits that might make a difference to DMA. It's readable as well as writable so you could read it, change 1 bit and write it. Turning on bits 0 to 2 might make a difference to DMA? This is supposed to be setup correctly by the gfx card boot ROM but that doesn't happen on an Amiga. Initialization is up to the 2D driver writer. I'm still not sure that DMA is going to be the Holy Grail of 3D performance. It sounds like you are already getting more out of the card than higher spec x86
. Take a look at the Quake III Arena hardware and test results here:
http://www.ultimatehardware.net/006.htmSurely they would have DMA enabled for their driver but with that lack of performance?
Also, I flashed my Cyberstorm MK3 and now I have PCI configuration info in my "ESC" settings. It supposedly fixes some PCI bugs too. I think delshay suggested flashing your BPPC if I read his English correctly :-/.
@delshay
No, I don't have any docs on the Permedia 3. You can see the test results above for how it compares to the Permedia 2. It still didn't perform well. It might be more worthwhile to reverse engineer a G-Rex PCI if you have enough electrical experience. Then you could use something a bit more modern with more gfx memory.
I'm not a big fan of overclocking I/O buses like PCI, Zorro or SCSI. It can cause timing errors when not in spec of the standard any more. I have done conservative overclocking of the CPU, GPU, and memory buses where I observed a large enough benefit and where there was better than average cooling. I overclocked my CSMK3 to 75MHz (rev 6 68060) and the memory with it but left the SCSI bus and motherboard speed alone by using a different oscillator. It's very stable and fast.
@Iggy
I overclocked the Voodoo 3 GPU with memory (SGRAM) and possibly other gfx card chips (gives a higher RAMDAC) by about 25%, but that shouldn't affect the PCI speed. The 2D performance improved modestly while any difference in my 3D tests would not have been statistically significant. I do not overclock my Voodoo 4 at all. I have read that it is not tolerant of overclocking (risk of burning out GPU) and there is not much benefit. The Voodoo 3 with SGRAM is a little faster than the Voodoo 4 at most lower resolution (bandwidth) operations by the way. The Voodoo 3 with SGRAM is probably faster with memory or gfx bus or both.