x68000 Performance Tweaks?

Started by spuci278, September 18, 2022, 12:34:43 PM

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What tweaks if any can you do to an x68000?  I know I had to define the additional memory I added in the BIOS (system.x) And you can upgrade the CPU if you want to cut trace lines, etc.  But what other software or hardware tweaking has anyone done?



Not familiar with any software performance tweaks, and the thought seems strange to me. I know that sort of stuff is possible in newer operating systems, but back in the DOS days there was no background bloat that could slow down your system. No multithreading and full level 0 program access to all resources. As such the only viable option for upgrading performance was via hardware upgrades.

Popular options is overclocking the system from stock 10mhz to 16mhz, to bring performance up to XVI levels. There were also CPU accelerator upgrade cards with newer, faster CPUS, such as 68030s to up performance, at the cost of compatibility.

The real questions is why you would want to. Most games are designed and optimized to run on a stock 10mhz system with 1-2mb of memory.


Sure, but for example in DOS you could load your device drivers and autoexec/config.sys into upper memory allowing for games and programs to run faster in the lower 512.  I believe you can create RAM disks in the Human OS and load games into it and/or use SRAM for additional programs. 

I did upgrade to 10 MB of RAM as a few games do require more than 2 MB but in short it's just my personality, if it can go faster then I want to make it faster.

I did look into either upgrading the CPU or overclocking but I believe both need you to cut trace lines and solder jumpers.  The soldering I am OK with but not cutting trace lines.  If there is another way to overclock please do let me know! :)



Human68k might look like DOS, but that is only surface level. Under the hood it is completely different, written from scratch and designed different. Human68k doesn't have the 640k program space limit that DOS was originally hampered by, which makes sense as the lowest end X68000 hardware came stock with 1 megabytes of memory. As for no cut CPU upgrades, the only way I can think of is by buying an accelerator like the Excellent cards. Otherwise you are going to have to get your hands dirty. The crux of the upgrades is bypassing the stock crystal which clocks the 68000 processor to 10mhz with one that overclocks it to 16mhz, along with a switch to let you toggle speeds. I am just speculating here, but I suppose you could permanently overclock your machine to 16mhz by soldering out the old crystal and swapping in a faster one.

I do believe there is more to upgrading the X68000 to 16mhz than that. I have seen mods done to the crystal of the floppy controller as well, either to speed it up, or to have it keep pace with the higher clocked CPU, can't say for sure.

The downside to overclocking your x68000 permanently is that some games don't work well, or at all running at 16mhz.


I own a X68000/16 with an physical FPU.
Does Float2. or float3.x something to the performance ?


Almost no games make use of floating point arithmetic, so the fpu is next to useless. Of the tiny minority of games that do use the FPU I can only remember, eh, Geograph Seal, I think.

And if memory serves me right float2 gives software emulated floating point functionality, which the few games can make use of while float3 is designed to make use of the FPU.

I actually have an FPU card myself, somewhere, though I never used or messed around with it.


Xak II and Crossfire EX both look for FPU on boot and will load float3 if the chip is found.

If you have a 10mhz machine, no point really, but XVI has a dedicated socket for it on the mobo (compact xvi has socket on the internal ram expansion board).  For me I just run float3 from boot.  Few games benefit, (Prince of Persia did iirc), but I had the socket and got the chip for peanuts, so why not?


Oh, yeah. Once upon a time, many years ago when I last had my Compact XVI open I do remember there being that FPU socket on my internal memory expansion unit. What is the name of the FPU module that fits inside that thing. If they are reasonably priced I might as well purchase one and pimp out my beloved machine.

Edit: After a bit og googlefu it seems what I am looking for is MC68882RC50A PGA chip. They are not too expensive, given the retro computing market in consideration. Of course they are all from chinese sellers, which conjures the "doubt" meme expression on my face. But I might give it a go, then never actually use it, as is par for the course for most of my retro purchases.