Is the Vortex Memory Expansion able to be used in addition to DkTronics ones for double the RAM accessed in different ways or do they conflict?
https://www.leboncoin.fr/informatique/2037599434.htm?ac=98969919
And another
https://www.ebay.com.au/itm/304136369105?hash=item46cff0b3d1:g:guYAAOSwwLFhE20k
As far as I know they can only be used as a kind of RAM drive, so they (in theory) should not conflict with the dktronics ...
I would try out (still got a SP512 laying around) but I'm a bit short on free time in the moment ...
They might conflict as they do not manage the ramdisable from the expansion connector. So you have to manage both expansion carefully.
They are also using "spare bit" in the gate array addressing for they configuration. It make it a bit more tricky to use than DkTronic's one and make it nearly impossible to use with interrupt enabled.
Last but not least, they work by enabling half a bank at a time (so either half lower or half upper), not that flexible.
You can built them into your CPC both.
But only use one at a time.
They do conflict. (32 KB blocks vs. 16 KB blocks).
Are there many in circulation?
The Vortex 512 KB expansion is a very scarce item. However, its BOS (Bank Operation System) is extremely powerful. For example you can write BASIC programs up to 288 KB.