A4000 112MB Memory hack

[discigabi]

A little while ago I had a discussion about the performance of the 112MB memory upgrade vs the 256MB BigRamPlus in an A4000...
I have managed to throw together a few tables and charts including comparisons and extended my 112MB upgrade doc with a Performance Test section including other information and comparisons as well. This particular comparison starts on page 47 using an A3660+r6.

Please, have a look if you are interested.
The link is the same:
http://bit.ly/A4000_112MB_upgrade_supplmtry

[esel]

So the 112 MB Hack is mutch faster then the Bigram. But thats not a surprise during the limitations of the zorro 3 Bus.

[discigabi]

Originally Posted by esel

So the 112 MB Hack is mutch faster then the Bigram. But thats not a surprise during the limitations of the zorro 3 Bus.

Correct. I think we all knew that the 112MB was faster but didn't know the difference ratio.

[hooverphonique]

The memory throughput with the 112MB mod is the same as with the stock 16MB.

[esel]

Sure it’s the same Speed, only the size has changed.

[discigabi]

There is a summary of the mean memory scores on page 31 if you want to see the details.

I didn't make a dedicated chapter for the comparison of the stock 16MB and 112MB as the mean scores of each config are very close to each other in readFast*, WriteFast* and Fast2Fast* test-cases.
Seemingly however, the 112MB mean scores are constantly below the mean scores of the stock 16MB by a very tiny bit in the aforementioned test-cases. --> The average difference of the mean scores is only ~1% (with the biggest diff of mean score being ~1.6% in Fast2Fastl) so it is definitely not significant.

I guess this ~1% is in the error ratio of SysSpeed and the expected differences between measurements due to the fact that these systems are not hard real-time systems. :-)
*plz note, that I did only 3-3 measurements for each configs in order to reduce the deviance from the "real" mean values... but 5-5 or 7-7 would have been better in order to get the convergence even closer to the "real" mean values.

[digitalMedic]

So has anyone that has done this mod noticed any problems with the Amiga or the OS? Does the Ramy adapter also allow for this mod? Where can one purchase a Romy and a Romy (I cannot find anywhere that offers them for sale), or are they DIY kits?

[hooverphonique]

Originally Posted by digitalMedic

So has anyone that has done this mod noticed any problems with the Amiga or the OS? Does the Ramy adapter also allow for this mod? Where can one purchase a Romy and a Romy (I cannot find anywhere that offers them for sale), or are they DIY kits?

Romy compatibility is discussed in detail on page one of this thread.

[digitalMedic]

Yes, the technical, and frankly theoretical, discussion related to whether the 112MB of ram would impact the 4mb ROM, but the same question at the end of the first page asking about any other downsides was not answered. What I am asking, and I assume the other poster's question was asking is, can anyone give real world, and practical, experience after this mod. Does it cause compatibility with any programs? Noticed any additional lockups or crashes? Any issues with expansion cards that may be linked to this mod? Since I am just starting out learning to solder, I don't want to chance it on my systems. So, before I pay someone to make the mod, I was just curious for some feedback. Because if there were unknown problems that revealed themselves, that means for money out to reverse the mod.

[torsti76]

Originally Posted by digitalMedic

Yes, the technical, and frankly theoretical, discussion related to whether the 112MB of ram would impact the 4mb ROM, but the same question at the end of the first page asking about any other downsides was not answered. What I am asking, and I assume the other poster's question was asking is, can anyone give real world, and practical, experience after this mod. Does it cause compatibility with any programs? Noticed any additional lockups or crashes? Any issues with expansion cards that may be linked to this mod? Since I am just starting out learning to solder, I don't want to chance it on my systems. So, before I pay someone to make the mod, I was just curious for some feedback. Because if there were unknown problems that revealed themselves, that means for money out to reverse the mod.

Theoretically, you can buy both Romy and Ramy directly from cosmos. I can give you his email address via PM, if you want.

I say theoretically, because he is out of Ramies at the moment (don't know if he will have made more of them).

The Ramy incorporates the two 4k7 pull ups for the RAM hack, too, so both can coexist.

I own an A4000T and just ordered the 4MB GAL for my 1MB Romy from cosmos. I plan to implement the FastRAM Hack, too, but have first to get hold of the 96MB JED file Meutoxo supposedly created. I'm not able to find it anywhere.
The PCB for the A4000T hack that goes on top of Ramsey has all pins easily accessible on top. So, it should be very easy to tap into the A18 and A19 address lines there to connect them to the larger ROMs. I even plan on doing this first before populating anything else on the board just to test the 4 MB Romy functionality.

[jaesonk]

Interesting threads on expanding the memory of the A4000 mobo.

On a related note, why are most accelerators limited to using 32MB SIMMs? I think only some of the A1200 accelerators can take larger SIMMs. Can the limited accelerators be hacked to accept 64MB & 128MB SIMMs. Four 128MB sticks on a CyberStorm, WarpEngine, TREX, etc would be nice.

Also, can an A3000 with a ZIP-2-SIMM adapter be modified to take on larger SIMMs on the motherboard?

[torsti76]

Originally Posted by jaesonk

Interesting threads on expanding the memory of the A4000 mobo.

On a related note, why are most accelerators limited to using 32MB SIMMs? I think only some of the A1200 accelerators can take larger SIMMs. Can the limited accelerators be hacked to accept 64MB & 128MB SIMMs. Four 128MB sticks on a CyberStorm, WarpEngine, TREX, etc would be nice.

Also, can an A3000 with a ZIP-2-SIMM adapter be modified to take on larger SIMMs on the motherboard?

The limit is in the spec of the CPU slot. In an A3/4000 the CPU memory space is max 128 MB. In theory, more can be achieved by "faking" Zorro III RAM, but it's impossible to do that with existing accelerators. Why? In contrast to the A3/4000 where the schematics and GAL contents are known, there are no available schematics or hardware configuration info for the "better" accelerators like Cyberstorm or TREX.

Also, this would require adding a CPLD and it's support components which is not practical because the accelerator cards are already crammed with components and traces and often have 4 or even 6 layers.

[Crumb]

Originally Posted by torsti76

Theoretically, you can buy both Romy and Ramy directly from cosmos. I can give you his email address via PM, if you want.

I say theoretically, because he is out of Ramies at the moment (don't know if he will have made more of them).

The Ramy incorporates the two 4k7 pull ups for the RAM hack, too, so both can coexist.

I own an A4000T and just ordered the 4MB GAL for my 1MB Romy from cosmos. I plan to implement the FastRAM Hack, too, but have first to get hold of the 96MB JED file Meutoxo supposedly created. I'm not able to find it anywhere.
The PCB for the A4000T hack that goes on top of Ramsey has all pins easily accessible on top. So, it should be very easy to tap into the A18 and A19 address lines there to connect them to the larger ROMs. I even plan on doing this first before populating anything else on the board just to test the 4 MB Romy functionality.

Sorry, I didn't notice your post, probably too late but here you have anyway. Just remove the .pdf suffix of the filename

[Crumb]

@digitalMedic


it works fine, just like the older 64MB mod (Meutoxo's or Bacterio's).


If you want to use speedramsey you may have to use a single 64MB simm.

[torsti76]

Originally Posted by Crumb

Sorry, I didn't notice your post, probably too late but here you have anyway. Just remove the .pdf suffix of the filename

Thank you!