Questions about Chip RAM vs Fast RAM vs Slow RAM

[Moto]

Hi Everybody,

I am just recently getting back into getting my Amiga 500 working again (while I wait for my new A1200 to come from AmigaKit!! Very excited!).  

So I cracked open the A500 case (since 1994) and I find that my system has:

stock 68k
a Spirit 2MB memory card
a 512kb Agnus chip (8370) and no 501 expansion card.

I remember using the extra RAM for a ram disk which I would then boot from it and do asm programming (k-seka!).

So last week I bought a 2mb Agnus chip like this one:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=985

I had to remove my 2MB spirit board because it would not fit with the MiniMegiChip daughterboard in place.   I pulled the old 512k agnus and replaced it with the MegiMini board (and installed the Gary socket).

Low and behold it works and I now have 2MB of chip RAM but I lost ALL my FAST RAM in the process.   I am able to run PALBOOT which is awesome because I can see what all those amiga demos are supposed to look like without being cut off on the bottom and also everything sounds more sync'd up.  You have no idea how horrible it was getting all these cool PAL demos and having to run them in NTSC!

So here's my questions:

1) What is slow RAM?  Is it just another name for chip RAM?
2) Does this MiniMegi chip have a total of 2MB or 1.5MB of RAM on it, because the A500 comes with 512kb right off the bat but is this now lost memory?
3) Can I use a 1MB Agnus chip without having a 501 card in place and use PALBOOT?  
4) What's the best configuration I should use for this 500?
5) What happens if I get a 501 card now that I have 2mb chip already?  Does that become fast ram?  Is it ok to have 0 FAST RAM?
6) Is PALBOOT the only way to get my A500 into PAL mode?  I have to run it every time I reboot and then reboot again.

Sorry for all the questions.  I've been out of the game for a really long time (but still have all my original books/disks/hardware that I've been hauling around all these years!)

Thanks!

-daniel

[Lockon_15]

Hi Everybody,
 
I am just recently getting back into getting my Amiga 500 working again (while I wait for my new A1200 to come from AmigaKit!! Very excited!).
 
So I cracked open the A500 case (since 1994) and I find that my system has:
 
stock 68k
a Spirit 2MB memory card
a 512kb Agnus chip (8370) and no 501 expansion card.
 
I remember using the extra RAM for a ram disk which I would then boot from it and do asm programming (k-seka!).
 
So last week I bought a 2mb Agnus chip like this one:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=985
 
I had to remove my 2MB spirit board because it would not fit with the MiniMegiChip daughterboard in place. I pulled the old 512k agnus and replaced it with the MegiMini board (and installed the Gary socket).
 
Low and behold it works and I now have 2MB of chip RAM but I lost ALL my FAST RAM in the process. I am able to run PALBOOT which is awesome because I can see what all those amiga demos are supposed to look like without being cut off on the bottom and also everything sounds more sync'd up. You have no idea how horrible it was getting all these cool PAL demos and having to run them in NTSC!
 
So here's my questions:
 
1) What is slow RAM? Is it just another name for chip RAM?
2) Does this MiniMegi chip have a total of 2MB or 1.5MB of RAM on it, because the A500 comes with 512kb right off the bat but is this now lost memory?
3) Can I use a 1MB Agnus chip without having a 501 card in place and use PALBOOT?
4) What's the best configuration I should use for this 500?
5) What happens if I get a 501 card now that I have 2mb chip already? Does that become fast ram? Is it ok to have 0 FAST RAM?
6) Is PALBOOT the only way to get my A500 into PAL mode? I have to run it every time I reboot and then reboot again.
 
Sorry for all the questions. I've been out of the game for a really long time (but still have all my original books/disks/hardware that I've been hauling around all these years!)
 
Thanks!
 
-daniel

Maybe it would be good to know the exact revision of your A500's motherboard.
But since you had 8370 and stock 512Kb ChipRAM, I'd guess that would be Rev5.
 
1) No.Slow RAM is pseudo-FastRAM. It's just sharing same bus as ChipRAM, which makes it second to true FastRAM.
2) 2MB soldered on Minimegi. Yes, stock 512Kb is unused.
3) Yes, PALBOOT is just SW using built in feature of dual PAL/NTSC Fatter Agnus.
4) With MiniMegi you already hit ChipRAM ceiling and you have PAL/NTSC switch feature in place. Switch to PAL to get demos working in full. For more RAM (true FastRAM), get a harddrive controller or even better, an accelerator.
5) That A501 in trapdoor slot will map as SlowRAM. Nice to have, but only if true FastRAM isn't around. FastRAM really make a big change, even if you're into some retro gaming.
6) It may be possible by bending some AGNUS pin (or grounding it, dunno) to set Amiga in permanent PAL mode.

[Moto]

Aaaaaah.  Thank you for that information.

Yes, my Amiga is indeed rev.5 board.  So basically the only good thing about the 501 board is that it has a battery backed up clock (which apparently leaks over time?)

I also have a 8372A agnus chip (1MB agnus) that I could use.
So which configuration is better?

A) 1MB agnus with only 512kb CHIP and 2MB Fast Ram (using 8372A and 2MB Spirit board which plugs into processor slot) == Total RAM 2.5 Meg

B) 2MB CHIP with NO fast Ram (using MegiMini only) == Total RAM 2 Meg

Having a 1MB agnus with only 512kb will still allow PAL Mode, so is the extra 1.5 CHIP memory utilized better than the extra 2mb FAST RAM is the question.  

This is my spirit board:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=1072

Unfortunately it can't be put into place with the MegiMini chip in place but it would be awesome to have 2MB CHIP + 2MB Fast !  Oh well, dreaming.

Thanks again!

-daniel

[Zac67]

Fast ram is always better (faster, you remember?) than chip ram - unless you need the chip ram for storing gfx or sound data - depends on what you're up to.

If you just have mechanical problems with fitting the fast ram board: locate an empty CPU socket (or more, as required) and use that to raise the Spirit board above the chip ram board. You might need to remove the metal shield and/or be unable to close the standard case though....

Another option is to add a standard 512 KB board. Depending on the original Agnus, the board configures as additional chip ram or 'slow' ram. If the (probable) latter is the case you can upgrade with a 1 Meg ECS Agnus (changing two board jumpers will be required) to get 1 MB chip without requiring additional space.

[AmigaHeretic]

So which configuration is better?

If it were me, I'd stick the 1 meg Agnus in there.  You'll show only 512k Chip RAM, but if you get an A501 then you can do the Rev 5 hack to give you 1 meg of Chip ram.  Then you stick the 2 meg of fast RAM back in.  Then you have 3 megs or RAM.   That's how I remember most A500s being set up.  

I think the best though would be to stick with the 2 meg Chip, then get some other kind of fast ram expansion.  

But there were quite a few games and demos that required 1 meg Chip ram later in the life of OCS/ECS.  


Either way with the 1meg or 2meg Agnus you'll be able to do PAL.  And I know exactly what you mean about the audio finally syncing in demos.  I think it went faster in NTSC so the music would end before the demo a lot of times.  Demos like State of The Art, the audio is synced to scene changes and things, so it's kinda weird.