A500 chip ram upgrade?

[Dandy]

I saw this listed on fleabay recently.  I have the proper revision motherboard the seller states is required (A500 Rev 6a), and am considering purchasing the kit to upgrade the computer to 1meg chip ram (well, I would send it to someone like Acill to do it, if he feels up to it).  Is there any reason to NOT do this?

As far as I remember, populating the empty places for Ram on the motherboard leads to losing the functionality of the trapdoor slot.

I also have such a mobo and wanted to solder the missing Ram directly onto the mobo, but gave up this idea after learning that this would disable the trapdoor slot.

[Dandy]

Ah, my bad.  I thought that the 512K trap door type of RAM expansion was fast mem, not chip mem.

The type of Ram in the trap door is called "Ranger" mem.
Not as fast as 'real' FastRam, but faster than CHIP Ram.

[Dandy]

It is exactly the same speed as chip ram. It suffers from the same slow down if there is a lot of dma activity, which is the only reason that chip ram is slow in the first place.

The trap door isn't actually ranger memory, it just appears at the same address as the 512k extra ram in the ranger prototype and then the third party boards which were based upon it. I believe this was true fast ram.

German Wikipedia:

„Ranger Memory“

Neben Fast-RAM und Chip-RAM gibt es noch eine dritte Art von Speicher – gelegentlich Ranger Memory, unechtes Fast-RAM oder Slow RAM genannt. Er befindet sich auf Speichererweiterungskarten für den internen Erweiterungsplatz im Boden des A500 bzw. auf dem Mainboard des A2000.
...

(My Translation: There's a third type of memory beside Fast-RAM and Chip-RAM - occasionally called "Ranger Memory", "pseudo Fast-RAM" or "Slow RAM". It is located on Ram expansion boards for the internal expansion slot at the bottom of the A500 respectively on the motherboard of the A2000.
...)

So it seems the trap door Ram was very well called
"Ranger Ram" and also was slower (that's why it was also called "SlowRAM") than the 'real' FastRam at the expansion port at the left side of the A500.

The fat agnus was an anti amiga inc (los gatos) project. Jay claimed it wouldn't work and that ranger should be the next step, which likely encouraged the chip guys even more to make it work.

First time I hear this story since being an Amiga owner (1988)...