Accelerated Amiga 1200

ACA1233n

The ACA1233n is something I could only dream of owning when I originally had my Amiga 1200 back-in-the-day.

It is an improvement over the previous ACA1233 with changes made to get the maximum memory performance from the 030 processor.

All 030 processors are reclaimed from somewhere so the chip doesn't look spanking new.

A big grin to the huge 127 Mb  boost in memory from my paltry 2 Mb fast ram expansion card.

There is a warning that comes with this board stating that the A1200s were not built correctly to specification. Capacitors can exist on the manufactured boards which impact the system timing/clock signals. It's not 100% clear if this means all Amigas' will have issues. Out of the box the card runs well without any crashes or problems in Workbench.

Sysinfo reports speeds exceeding a stock A3000. MMU should be available on the 030 processor installed on the 1233n. In general these are not used for Amiga games. 

In short, the 030 is an 020 core with MMU support running at 40 MHz.

Another cool feature of the accelerator is the ability to load ROM into memory. The board technically has 128 Mb but 1 Mb contains the ROM. Performance is supposed to be improved. I can't say that this translated into Sysinfo improvements or was noticeable with the way I use my Amiga. What is nice is the ability to change the system ROM without buying new chips or running a kickstart disk. OS 3.1.4 has now been released and it can be used immediately without needing to wait for the ROM chips.

Timing issues

Immediately I found that many games would cause memory exceptions or unexpected reboots. This was happening every time without fail. I wasn't sure if this was board compatibility or the timing issue. The card can be downgraded to remove the extra memory and disable aspects of the processor. After trying all options (apart from disabling the card entirely) I decided that it was time to get my soldering tools out to remove the capacitors.

Removing the extra capacitors should not be a problem for any A1200 as they are redundant to the design. The final design actually excluded these, but due to communication issues with the factories, the extra capacitors were still assembled. 

The Wiki from Individual Computers has a good image showing the location and label of these additional components.

Capacitors E123C and E125C installed

Capacitors removed

Removal was simple with a hot air gun. Once these were removed and the system restarted and the games which previously crashed now worked every time. 

Performance

Running games is immediately noticeable with titles such as Wings and Frontier. I tried playing these with my standard 2 Mb expansion card and I can't believe I used to play these games with such horrible frame rates. Acceleration will not deliver silky smooth graphics and improved resolutions as this isn't a graphics upgrade, but it does deliver games which were just unplayable in the past. 

Some games now run a tad faster than I think they really should and this is clearer in older games for the A500. 

Workbench performance is much harder to judge. The memory plays a much bigger role in the apparent performance gains. My Workbench is running from compact flash and this is a massive improvement for even an unaccelerated OS.

WhdLoad would run with the 2 Mb fast RAM. This would cause some screen flashing and other odd screen blanking when loading up games. With the ACA1233n I don't get these anymore.