Re:3600 MHz Raspberry Pi 5 with Liquid Nitrogen
by mrguyorama on Wednesday November 13, 2024 @01:27PM
(#42128594)
Older CPUs didn't have a range of performance. They either worked at a clock speed, or didn't. If you put in a very high rate crystal, the CPU would either work at that higher rate without cooling, or not work without cooling. Clock speed was a constant.
>I didn’t even measure the clock speed - just wrote a little program (I think it was in QBasic) that calculated factorials or something (don’t remember the details), then measured performance difference between no cooling, ice water, and liquid nitrogen.
>My measurement technique was extremely simplistic - how much wall clock time does it take to do this computationally-intensive task. It ran faster with ice water, and even faster with the liquid nitrogen (until it died from condensation).
There is no world in which a 286 has a program that runs "slow" without cooling, and fast with cooling. If a clock speed "needs cooling", it's because the CPU crashes otherwise. If jdenning changed the crystal, THAT'S what increased the CPU speed. They seem adamant that wasn't the case though.
>I didn’t even measure the clock speed - just wrote a little program (I think it was in QBasic) that calculated factorials or something (don’t remember the details), then measured performance difference between no cooling, ice water, and liquid nitrogen.
>My measurement technique was extremely simplistic - how much wall clock time does it take to do this computationally-intensive task. It ran faster with ice water, and even faster with the liquid nitrogen (until it died from condensation).
There is no world in which a 286 has a program that runs "slow" without cooling, and fast with cooling. If a clock speed "needs cooling", it's because the CPU crashes otherwise. If jdenning changed the crystal, THAT'S what increased the CPU speed. They seem adamant that wasn't the case though.