Saturday, May 5, 2018

How much power does Star Rider actually use?

I've been looking into making a replacement power supply PCB for Star Rider since my original one is currently not working.  I've been running Star Rider off an ATX power supply for years and it seems to work fine.  But newer ATX power supplies are starting to really get cheap on the -12 V current.  I tried a brand new one and it didn't have enough -12V juice to run the game properly.  So I decided to do some tests and see just how many amps the -12V (and 12V) rails need to provide to run the game.

Not pictured is the 5V power supply that I rigged up.  The current on the 5V power supply I wasn't able to accurately measure, but it seems to need 6A, maybe even 10A, to be stable, so that is by far the most demanding of the power requirements.

Conclusion: both the 12V and -12V supplies seem to need around 0.51A so an ATX power supply with 0.8A on the -12V rail should do the job; the newer one that I tried only put out 0.3A which is why it failed miserably.

Hopefully they still make ATX power supplies with 0.8A on the -12V line.  The one that I am successfully using was made for a Pentium 4 so it's pretty old these days.


  1. From a quick look at some ATX product listings, it seems most are 0.3A on -12V, but I found some Corsair supplies that are 0.8A. Do you know what Star Rider uses the -12 for? How exactly does it fail when there's not enough current?

    1. On the expander board, the -12V goes into a 7906 and appears to produce -6V.
      On the sound board, the -12V goes into a 7905 to produce -5V. I can't see that the -12V is actually used any other way.