ragen-fio
Member
This past week, I decided to return to an old PS1 overclocking project based on the Si5351 clock generator.
The idea came to me a few years ago when I read an old "guide," if we can call it that, in which someone suggested replacing the clock generator on a PS One with an 80 MHz crystal to give the CPU a 40 MHz frequency. That person didn't take into account, perhaps due to a lack of knowledge of the console's architecture or by intentionally omitting it, that the audio and CD drive would also be negatively affected by that frequency increase.
At the time, having an abundance of PU-18 motherboards, it was much easier for me to just replace the original 67 MHz crystal with a 90 MHz one. The results were predictable: the number of games that could be loaded dropped dramatically, the audio went completely nuts, the CD drive spun like crazy, loading times were sometimes shorter, and games ran much smoother. What impressed me the most was Driver 2, where with the stock clock, the FPS dropped below single digits in some situations, but with the CPU at 45 MHz, I don't think they ever dropped below 20. After tinkering with it for a few days, I abandoned the project due to lack of time, only to resume it later with the idea of finding a way to separate the CPU frequency from that of the SPU/CD, which I found in the Si5351. I created some code for Arduino in which I used a button to provide the CPU with a variable frequency in 5 MHz steps from 67 to 90 MHz, and the SPU/CD with a fixed frequency of 33.8688 MHz. Unfortunately, the results (especially with the audio) didn't change much, except for game compatibility, which improved when I installed a PSIO to simplify my life with loading games and completely eliminate possible problems related to the CD drive's mechanism. And again, due to the usual lack of time, I had to put the project on hold for a couple of years but am resuming it now, hoping to make at last a step forward.
P.S. If anyone has any suggestions, I'm all ears.
P.P.S. Playing Gran Turismo 2 @45MHz was a sinful pleasure.
Don't pay attention to the wiring because it was temporary and my intention was for it to be functional and to keep the wires as short as possible, aesthetics was not the main goal.
The idea came to me a few years ago when I read an old "guide," if we can call it that, in which someone suggested replacing the clock generator on a PS One with an 80 MHz crystal to give the CPU a 40 MHz frequency. That person didn't take into account, perhaps due to a lack of knowledge of the console's architecture or by intentionally omitting it, that the audio and CD drive would also be negatively affected by that frequency increase.
At the time, having an abundance of PU-18 motherboards, it was much easier for me to just replace the original 67 MHz crystal with a 90 MHz one. The results were predictable: the number of games that could be loaded dropped dramatically, the audio went completely nuts, the CD drive spun like crazy, loading times were sometimes shorter, and games ran much smoother. What impressed me the most was Driver 2, where with the stock clock, the FPS dropped below single digits in some situations, but with the CPU at 45 MHz, I don't think they ever dropped below 20. After tinkering with it for a few days, I abandoned the project due to lack of time, only to resume it later with the idea of finding a way to separate the CPU frequency from that of the SPU/CD, which I found in the Si5351. I created some code for Arduino in which I used a button to provide the CPU with a variable frequency in 5 MHz steps from 67 to 90 MHz, and the SPU/CD with a fixed frequency of 33.8688 MHz. Unfortunately, the results (especially with the audio) didn't change much, except for game compatibility, which improved when I installed a PSIO to simplify my life with loading games and completely eliminate possible problems related to the CD drive's mechanism. And again, due to the usual lack of time, I had to put the project on hold for a couple of years but am resuming it now, hoping to make at last a step forward.
P.S. If anyone has any suggestions, I'm all ears.
P.P.S. Playing Gran Turismo 2 @45MHz was a sinful pleasure.
Don't pay attention to the wiring because it was temporary and my intention was for it to be functional and to keep the wires as short as possible, aesthetics was not the main goal.
