Radeon/Mediator as FastMem (HowTo)

[Piru]

Is the mem as fast as Z3 memory?

Much slower, especially when reading. VMEM is not meat to be read.

[Piru]

Why will it only work on ZIII?

ZIII can be addressed directly.

Could it also work on an accelerated (030/040/060) Amiga 1200 with a mediator?

No

[Piru]

If someone wants to buy me a Mediator for my A1200, I'd be happy to write it.

You're aware of the fact that many applications allocate memory as assume it doesn't get paged away? And that MEMF_PUBLIC doesn't work as a "swappability" flag?

[Piru]

The application would never know if the memory was paged or not.

It isn't that easy. Even the most advanced virtual memory system ever written for amigaos doesn't work right for all applications. You need to have blacklists of misbehaving applications (or whitelists of well behaving ones).

Just look into http://aminet.net/package/util/misc/VMM_src and you'll soon figure out it is hardly trivial, nor can it be made 100% transparent.

[Piru]

Huge difference between paging memory from disk and paging memory from bank switched RAM.

That part is true. It removes the trouble of accessing the memory while in Forbid/Disable. That, however, is just one of the problems.

Additionally the performance would be really bad. Much slower than chip memory.