Viper 1240 to 1260 upgrade

Upgrading a Viper 1240 accelerator card from the 68040 processor to 68060. What’s involved? Parts needed, benchmarks, and screenshots follow. Also how well does it run Quake and Doom?

I couldn’t help myself. Within weeks of getting my Viper 1240 accelerator, I went and purchased a 68060 processor to upgrade it.

The 68060

We all know the 68060 is a vastly superior CPU to the 68040. Larger cache, faster FPU, better pipeline, faster clockspeeds, and lower voltage (often resulting in cooler operation). All these improvements leads to a processor twice as powerful as its predecessor. Can you imagine a CPU coming out today from Intel or AMD giving 100% performance improvement over the previous generation?

My 68060 is a XC68060RC50A revision 5 with 01G65V mask number. The XC parts were produced before Motorola “qualified” the chip at revision 6. XC chips contain a few bugs. However, these have all been worked around in software and library updates over the years. There is nothing to worry about. The later Rev6 MC chips are known to be better at overclocking, and run cooler. Most XC68060’s are still a lot cooler that 68040’s due to smaller transistor sizes and 3.3v power.

The 68060 needs a suitable Crystal oscillator also. 060 chips run at a 1:1 clock rate to the oscillator. 040 use a 1:2 ratio half the crystal frequency. I switched from my 80Mhz crystal (needed to get 40Mhz to the 040), to a 56Mhz one.

As you can see, someone in the past had superglued a heatsink on to the processor. I trued removing with Isopropyl alcohol, then makeup remover, but it wouldn’t shift. I managed to remove it with Butanol in the end.

Voltage Regulator

Visually the 68060 looks very much line the 68040. They share the same socket, but have a different arrangement of pins on the underside. The biggest difference between the two is that the 060 runs exclusively on 3.3v. The 040 uses 5v. This means unless you set the accelerator card voltage (or use a separate regulator) to 3.3v, the processor will get damaged. The Apollo and Viper line of cards have power pinouts. These pinouts allow the motherboard supplied 5v lines to be sent to the processor directly. Alternatively by removing the jumpers, a regulator board can be attached for processor core voltage conversion.

I didn’t have a spare regulator board, so made an request for one on AmiBay. I ended up getting one for a reasonable price from this seller. This is a new and modern design based on the PTH04070W part. Original Apollo regulators would also work, or any of the other replacement linear regulators like this one.

Testing and Benchmarks

With the regulator and 060 installed, its time to power on and see if it all works…. Yes! Workbench starts up as normal and I can go straight into benchmarking with Sysinfo and SysSpeed.

Starting with a speed of 56Mhz, the 060 scores 43.94Mips in Sysinfo, and 74.9Mips in Sysspeed. An almost 3x improvement over the 68040 40Mhz score of 28Mips (reading from Sysspeed).

Moving on to a 60Mhz crystal the score goes up to 47.09Mips in Sysinfo, and 79.7Mips in Sysspeed. I might try the 060 at 66Mhz at some point.

Conclusion

So there we have it. A MACH130 Viper can be upgraded to 68060. My card runs very stable at 66Mhz with the revision 5 processor. It also runs a lot cooler than the 68040 that I tested here:

Neil – 8bitplus – 2025