Amiga500: Lazarustorm/PiStorm vs ACA500plus

The original Amiga 500 is a great machine, but its 7MHz CPU is a bit slow at times and the 512K of base memory quite limited. We take a look at two accelerator cards that increase the CPU speed significantly and also bring a large amount of extra memory to the table. All the while these cards don’t require you to open up your A500, but instead they fit on the expansion slot on the left side of the Amiga, making the process very easy and reversible. Let’s take a look at the PiStorm based Lazarustorm and the Individual Computers’ ACA500plus.

Music: A Little Wonder by Spino2006

0:00 Introduction & Explanation
15:13 ACA500plus Setup
20:06 ACA500plus Benchmark
24:25 ACA500plus Stealth Mode
26:16 Kickstart 3.1 Issues
31:18 Lazarustorm Benchmark
37:30 Comparison and Closing Words

[ConradVassallo]

Thanks for sharing the video. I actually have both solutions on hand. Initially, I bought the Lazarus for Pistorm, but I couldn't get it to work with my rev5 A500. The instructions weren't clear to me when I purchased it, and I didn't realize I needed to add the 7Mhz clock signal to the expansion port. All I found was that it wasn't compatible with rev5 boards. Your video clarified things for me, so now I can switch between the two solutions as I like. Thanks again for the helpful tip!

[Shmbler]

The emu68 1.0 release has come a long way. When I built my PiStorm 3 years ago, I quickly became disappointed because so many of my favorite games had issues with it. Out of frustration, I then purchased an ACA500+. One of my best buys ever. Even though it ran fine at 42MHz, , shortly after I added an ACA1221 just to have the 020 for the games that specifically supported it (like Ambermoon). Two years ago I digged out the PiStorm again for trying the experimental emu68, and it felt already a lot more compatible than the linux based emulator right from the start. And yesterday, I tried the 1.0 release of emu68 and everything I throw at it just works perfectly. All the compatibility issues I had seem to be gone. Absolutely amazing. The only one thing that PiStorm/emu68 is really missing out on is a way to easily switch the emu68 configuration. Right now, you'd have to prepare and swap SD cards with different configs, which kind of sucks. Especially if you have no LazarusStorm adapter. The ACA500+ is -a lot- more versatile in that regard.

[LinuxRenaissance]

Holy Moly your channel is awesome! Subbed.

[chainqk]

Also one more thing about the 8MiB RAM limit you say and you try to combine it with chip RAM... - there's no such thing. The address space of any Amiga that uses the 68000 is 24 bit (16MiB) and in that address space you can have up to 8MiB _continuous_ Fast RAM, in the Zorro II expansion range from to In addition, there's up to 2MB chip RAM possible, at the start of the address space, from to There are also smaller "holes" of the address space, where additional RAM is possible, for example the a range from which is reserved for the 512KiB trapdoor expansion (usually), but actually up to 1MiB here can be used. So that's 9MiB of Fast RAM already, and we still did not take Chip RAM into account... There isn't really a hard limit, but there might be diminishing returns trying to use every small block that would be possible, really. On the Amiga 600, the ACA620 can map up to 10.8MiB of Fast RAM into the 24bit address space - plus 2MiB chip RAM is possible, on top of that.

I have no experience with the ACA500, but i _think_ what you see, is a bunch of Fast RAM eaten up by disk buffers. Amiga filesystems can be quite obnoxious with RAM requirements, especially when used with large media. I see the installer copying over PFS3, not sure if that was used, but both that and FFS can eat up megabytes of RAM for buffers easily. This can be controlled in HDToolBox though, and reduced (on the expense of losing some performance).

[johnwiesen]

Very nice video. I have a ACA 500+ mine runs at 42MHz ok, I put a heatsink on it. I use my ACA 1233n card with a 68882 fpu I got the X-Surf for the ACA 500+.But I have a PiStorm for my A1200.

[chainqk]

Pi 4 is supported, Pi 5 won't ever be (most likely) because its GPIO functionality is behind a PCIe slot, and while PCIe has amazing bandwidth, it has appalling latency, and PiStorm needs low latency to be able to react to the 68k bus in time.

[janialander]

I have one those late production A500's with 512 kb chip ram, but Agnus chip is Fat Agnus, meaning it supports 1 meg of chip RAM.

[alexany]

How is it possible that you have 1Mb Chip-RAM with the ACA500plus if you only have the old regular Agnus on your Amiga as you explained in the introduction ?

[jimboblivesforever]

Used to have the ACA500+. Good card, but not without it's problems. One was contact with the slot. One A500 I had didn't have it's original rubber feet, and this tiny difference in angle had a big effect on the reliability of the connection. The other A500 had the original feet, but connection still wasn't perfect. I guess one might have similar problems with a Lazarustorm, for others it might not be a problem at all with either card. What put me off the ACA500 and made me sell it was the fact that the A500 is already a huge computer on it's own, which is why I prefer an internal solution. And just when I pulled the trigger on a Terrible Fire PCB and had collected the first parts for it, I became aware of the PiStorm. Which I still haven't bought - I just can't decide :-)

[TwickenStep]

People mention that the cpu will interfere with the lazurus storm if not removed and that if you dont remove it, it could be unreliable? Did you encounter any issues running the amiga with lazurus storm when keeping the cpu in? I dont really mind if its hacky, i think if it works its really good.

[LogicWheels]

What is the revision of your Amiga PCB? Seems that the Lazarustorm is not working on Rev. 5 motherboard.

[SewersideFPV]

No one i know with a Lazaurstorm purchased in 2025 can get it working without taking the 68K CPU out. In this video there seems to be a new addition... a wire going from a jumper to a sidecar pin.. why? Is this how you get your Lazarustorm working as advertised?

[TiamatsScale]

I much prefer the ACA500+. Mine does the 42 just fine if i wanted to. With the PiStorm .... well ... it doesn't feel right to put a modern Porsche engine into a Beetle from the 50s.

[naib_stilgar]

A plipbox to get the amiga online is both very inexpensive and easy to build. Cheers!

[xantam]

Maybe you could add an A314-cp to the ACA to get Wi-Fi. Costs around 35€ + a Pi Zero2 W.

[pederb]

I have to give a downvote because of all the talk. Bla bla bla of how great it is. And almost no showing how superior in every way the pistorm is.