A500 (r6a) 1MB CHIP RAM Modification: Caution dialup users: excessive H/W pr0n!

[Zetr0]

@ikonsgr

Thats not what BLTCON0 is actually saying - its quite a technical post, so let me try to explain.


In the A500 -

The CPU and Custom Chips only have 512KB of RAM to work with, so each get a time slice to use it... this means the CPU has to wait around until the Custom chips (Paula / Agnus / Denise / Gary / CIA A and B) have all had their way with it...

In most cases this means the CPU is slowed down to fetch data to processs it only to have to wait unitl its time slice to put that data back again and fetch another.

BLTCON0's explanation basically comes down to - The busier the Custom chips are the less time the CPU gets to the CHIP memory pool and the performance suffers over all.

FAST ram alleviates this problem, it can fetch memory and process it at its own speed and then puts it in CHIP ram so this improves processing (not the processor) just the processing of data is more efficient.

So with one of Kippers memory adapters it increases the ability to process by 33%

Simply put things that requires a lot of CPU processing (like polygons) will get a net gain in speed due to better efficiency where the CPU doesn't have to wait for the Custom Chips.

Also with more memory you have the option to add buffers and improve performance again - especially with disk and hard-disk access.

[ikonsgr]

I've just made it! Now i'm a proud owner of an AMIGA 500 with 1Mb chip ram!

P.s Be extremely carefull when you cutting the jumper joins! It's very easy to slip and cut nearby lines.

[ikonsgr]

@Zetro well, what you have discribed is EXACTLY what i have in mind too!
So bottom line:
Ιt is true that,by adding extra fast ram, you WILL get an overall beter performance with games (i think you will probably see improvement in "dead times" and slowdowns in "heavy action" game scenes, where probably caused of this "time sharing" of chip ram bus between cpu and custom chips, right?) , BUT this gain will not be "flat": the more the custom chips utilize chip ram the more peformance gain you will get!
Did i "get it" right?

Now about the "buffer options" you mentioned,to tell you the truth my greatest concern is, if fast ram can help with specific games,the kind of multi disk games, that require very often access to disks and so wating times and pauses are making it VERY annoying to play them from disks! Typical example many great adventures like universe, curse of the enchantia, legend of kyrandia etc. In these kind of games, the existance of fast ram will it helps to shrink the wating times of loading (and perhaps decranching) since the cpu can have access to fast ram AT THE SAME TIME of floppy controller loading data from disk to chip ram (which i think it's not possible if you only have chip ram)?

[Zetr0]

Dude!

you can *mount* RAD disk(s)- this can take a full copy of 960kb of a DISK IMAGE into memory, other DOS or NDOS and it will work fine with games that look for volume names for their data.

I have done this in the past with Flash Back, Road Rash, Wing Command to name a couple.... this massively improves loading times between disks and reduces the need to swap them - obviously

The more memory you have the more you can use.

Simply put, its about performance on an average net-gain - as such ones operations with the system will be improved overall by the addition of FAST RAM (in pure calculation this can be as much as 33%) where as a general estimation of workbench would be as much as 25% with kickstart copied to RAM.

With the use of a hard-disk you can add buffer's to the device to improve data transmission - as well as use of a RAM disk -

All in all, to not get one when you can - to think of this as no real use to disk games and such like is some what crazy!

[ikonsgr]

Ok,i get it!
You think if i combine the kipper2k's ram card along with an 68010 cpu,i will see a noticable improvement in overall performance in games or not?
(and yes, i'm focusing on games, because this is what i mostly use my amiga 500 for! )

[Balooga]

You may see an increase in speed in games like Stunt Car Racer, FA/18 Hornet, Elite Frontier, F1GP and other polygon pushers that rely heavily on raw CPU processing.

You will not see any improvement to 2D side scrollers as these games rely heavily on the custom chips. Unless the game is written to take advantage of additional RAM, e.g SWIV (WHDLoad version).

[ikonsgr]

In the wating times of repeated loadings from disk, (like in many adventure games) will i see any "shortening" of these anoying waiting times? I was thinking, maybe this will be true, since the cpu can have access to fast ram AT THE SAME TIME with floppy controller loading data from disk to chip ram...
Of course i can make rad drives and load 4 disks with 4mb fast ram, but every time i switch off amiga, i must remake the rad's!

[Balooga]

You will not see a decrease in loading times unless the game was written to take advantage of the extra ram.

Alternatively, you might try SmartCache which caches the floppy in ram. But this assumes that the game uses the operating system's trackdisk.device.

[Zetr0]

or you can mount a RAD disk device

[Balooga]

or you can mount a RAD disk device

Yes

Or alternatively, copy the entire WHDLoad game into RAM and run it from there.

[rkauer]

Another important advantage of making the 1Mb chip RAM hack is you can use better (more colours) and higher resolutions in Workbench and serious software applications too.

If you have a HD in your A500, you can run Directory Opus 4 in four colours without spending all the Amiga memory.

[ikonsgr]

.... unless the game was written to take advantage of the extra ram.

That's EXACTLY what i CANT understand! I happen to be a pc programer and i NEVER deal with "positioning" of programs or data in system's ram! This is done automatically by the OS!
So, i assumed that (of course you may say you "assume" wrong!this is amiga where talking about! ) ,when fast ram is detected by the amiga,it will ALWAYS utilizes it, by loading code and data of ANY program (and not just game) in fast ram, in order to achieve maximum efficiency of program execution! Moreover by doing that, will also give almost all bandwidth of chip ram bus, to custom chips,and thus, raise the max efficiency of them too!
I dont understand why there is a "need" for the program itself to do that, and amiga can't do it automatically in EVERY occasion! I suppose ram assignment is something that is done in the very "low level" of an OS (in amiga's case, maybe this is done by kickstart), so even if a game bypasses workbench (which i think is something typical with amiga games), utilization of fast ram would always be done!
The only possibility i can think of, of WHY this is NOT happening, is, if the programers of most games FORCED (in game's code itself) program and data, to be loaded in chip ram address area,and so any benefit from fast ram is simply "vanished"
Is this REALLY what's happening with amiga games,and if so, WHY THE HELL THE DID THAT?

I REALLY would like if someone could explain that to me!

[rkauer]

You nailed the issue in the head.

Some old (or badly written) games allocates memory areas assuming they will be there.

Some old (and very badly written) A500 games expect to always have memory on C0000 location (the expansion slow-fast RAM area) and fail miserably to load if nothing is there.

Of course, almost all games do not load Workbench to have the maximum possible RAM available to themselves.

[Balooga]

The only possibility i can think of, of WHY this is NOT happening, is, if the programers of most games FORCED (in game's code itself) program and data, to be loaded in chip ram address area,and so any benefit from fast ram is simply "vanished"
Is this REALLY what's happening with amiga games,and if so, WHY THE HELL THE DID THAT?

Game developers back in the day tended to code close to the metal, which mean throwing out most of the OS.

[ikonsgr]

So, you are telling me that, if workbench is not loaded, then practically any fast ram is absolutely useless, because without workbench, no program can utilize it!
And since allmost all games does NOT load workbench they never utilize fast ram!
Man, amiga never stops to surpise me....

P.s I just though of something: what if, i first load workbench, and then try to run the game from there, in order to utilize fast ram?
I remembered that some games do that anyway, but ,can it be done with other "auto boot" games? And will they utilize fast ram that way?