CPU Performance and RAM

Question- Does the type and speed of RAM affect gameplay of a real Robotron machine?

Answer- per Yellowdog on KLOV-

  • As long as the RAM can serve up the bits faster than the CPU can handle them you are fine. The clock speed is 1MHz or about 500nS. The original RAM was 450nS RAM. So anything faster than that is good.

Question- Do you know the difference between 150nS and 450nS RAM?

Answer- per Yellowdog- Probably nothing. The difference was what speed the chips were certified to run at.

  • They make 20,000 chips. They have orders for 2,000 chips at 150nS, 4,000 chips at 250nS and 12,000 450nS chips.
  • They will start on the chips and when they get 2,000 chips that test good at 150nS, they turn the clock down, dump all the chips that foiled back into the bucket and start testing for 250nS until they get the 4,000 chips that that they need.
  • Then they turn the clock down again, dump all the chips back in the bucket and test until they get the 12,000 450nS chips they need.
  • Could some of those 450nS chips test good at 150nS, absolutely. It was luck of the draw literally.

Question- Why does the game slow down at the start of busy waves, like the upper Brain waves?


per Larry DeMar (Aug 2014)-

  • There are 2 tiers of objects. The higher priority objects (player, shots, spheroids, Quarks, and shots from the last two) aren’t affected by CPU-bog until it gets really, really bad. The other objects (grunts, hulks, tanks, humans, posts) are in a 2nd tier and they will all slow down if there aren’t enough CPU cycles to do everything. The game would be unplayable if the player’s controls were affected this way.

per Yellowdog-

  • The issue with the blaster fire in the higher waves is simply the draw/calculation loop.
  • You (the main character) are #1 on the draw list. Then come your bullets. Then come the family members, then come the moving objects and then finally come any enemy missles, ray blasts, bullets, etc.
  • So if the processor can handle 75 objects drawn in a single frame (an arbitrary number, I don’t remember the actual number) and there are 95 objects, the last 20 won’t get drawn until the next frame, so they will appear “frozen”.
  • There is arbitration logic to make sure that objects within classes get equivalent time slices. So they don’t stay frozen for long. Especially since you are free to move and shoot at full speed until you kill off enough objects to get the number down to a point that the CPU can handle all of the objects every frame.
  • That is why all of the good players know to take advantage of that momentary period where you are moving 2 to 3 times faster than everything else to kill the most dangerous and closest enemies as quickly as possible.

Why does 4116 RAM run so hot it will burn your finger, yet 4164 RAM runs cool to the touch (less prone to heat failure)?

  • 4116 RAM requires +5V, -5V, and +12V to run.  4164 only requires +5Vdc. But that is NOT the reason for the heat.
  • per Yellowdog- 4116 RAM is 16K so it uses the full memory.  4164 is 64K so the chip is only using 1/4 capacity thus runs cooler.


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