Stupid ACA1221EC question regarding RAM

[Amiga1992]

So I read the description on the ACA1221EC at Amigakit's website, it says this:

"16MBytes physical memory. 9MBytes of this physical memory can be used as fastmem, and up to 7 MBytes can be used as a ram disk. "
Does this mean I can only use 9MB as Fast RAM? What is the purpose of using a RAM Disk in this way if the system always has a RAM disk that pools from available RAM?
Also would MapROM eat up 1MB of those 9 making it actually an 8MB expansion (if I use MapROM)?

I am looking at different accelerator options and I would be very happy with 16MB but not with 9MB. I don't need a "RAM disk" whatever it means this is different form what we already get on the Amiga.

Also I am guessing this EC model cannot be upgraded like the previous one? Maybe I should look for someone selling a standard 1221, as it seems it can have more RAM.

[nobody]

Because that EC edition cannot see 16mb but only 8?

[Daedalus]

But the previous version was a swizz, remember? </sarcasm>

9MB are about as much as can be squeezed into the 24-bit address space, just like RAM-only boards. The extra 7MB can be accessed by special software but not the system due to the design of the board, so with a custom RAM handler you can store up to 7MB in a RAM disk without affecting the available RAM - this is the advantage of the RAM disk using that card. Of limited use, perhaps, but better than not having access to the 7MB at all.

[puppypc]

the 1221EC has the same processor as inside the amiga, only with a higher clock speed. This is more or less the maximum RAM you can have without a more powerful accellerator.

[Amiga1992]

I see, so it's a limitation of the CPU? But how did the previous 1221 allow for 63MB of RAM?
ACA1221
Processor (CPU): 68020 (full) 16.67 MHz
Memory (Fast RAM): 9 MB (optionally expandable to 17 MByte / 33 MByte / 63 MByte at extra cost)

Confused.

So yeah this EC model is not for me, I need at least 16MB of RAM.

[Kelv]

yup, the 'ec' is pretty much designed for WHDload use.

[nobody]

Because the other card is not EC. It has the good processor with higher bus and sees more memory.
Also me I feel the card doesn't fit with aca500+, the 8mb of ACA get wasted, and another 8mb get wasted from the aca1221ec. So you have 24mb and use only 8 :P
That 1221ec is ok if you have the simple aca500 with 2mb ram.

[Daedalus]

The EC in the name comes from the version of the CPU used. the 68EC020 and 68020 are essentially the same, but the EC version only has 24 address lines, whereas the non-EC version has 32. This means the EC version of the CPU is cheaper, but can only access 16MB of address space, much of which is already occupied by various other parts of the machine (Kickstart, custom chips etc.)