It's too bad the A530 apparently maps its 32-bit Fastram in the 24-bit address space; otherwise you could install two of the GVP 16Mb SIMMs and have 32Mb. At the time it was made, however, 8Mb was a huge amount of memory especially for an A500. I wonder if there is some way to change it so that it maps the memory into 32-bit address space.
All in all, it's a nice accelerator and has a nice DMA SCSI controller built-in, which other boards like the Derringer don't have. When you try to use a C=A590 with the Derringer or VXL030, you're probably going to run into the dreaded 24-bit DMA problem (i.e. the 590 can't dma into the 32-bit RAM on the accelerator and so harddisk transfers crawl; same thing happens with an A2091 and a 32-bit cpu controller......e.g. 32-bit memory with a DKB2632 piggybacked on the C= A2630 or in an A4000). So you're left with using some kind of software patch to make i/o transfers remotely bearable or use a non-dma scsi controller a la Dataflyer, Trumpcard or the like.
So you see GVP knew what they were doing.