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The Sony PlayStation CPU runs by default at ~33MHz, with this O/C mod you can take the CPU frequency to 40Mhz, enough for eliminating “CPU-intensive” slowdowns. However if you suck at soldering you could “brick” your PSX. Be careful.


Welcome to the Playstation overclocking guide! This guide will show you how to increase the overall performance of your Playstation and/or PSOne console. We will be performing this modification on a PSOne console, although the procedure is the same for the chunky Playstations. As with any hardware modification, your results may vary, and UCM is not responsible for damages or unsatisfactory results. Please make sure you are skilled with soldering before you attempt this mod!

Tools you will need

*Phillips Screwdriver *X-acto knife or Jeweler's screwdriver *Soldering iron and Solder *4-pin Crystal oscillator Where do I get one of these?

About the procedure

What we are going to be doing is fairly simple: We will be intercepting the 67 MHz clock signal that is sent to the CPU. The CPU internally divides whatever signal it receives by 2, this results in a 33.86 MHz operating speed. Today we will be disconnecting that 67 MHz signal, and installing an 80 MHz crystal oscillator that will overclock the CPU to 40 MHz.

Opening the PSOne (and Playstation) is very simple. Just be careful when removing the CD-ROM assembly, as the data ribbons are very fragile and easy to damage. Once you are looking at the motherboard, you need to familiarize yourself with the components you will be dealing with: The CPU, the clock-generating PLL, and the Voltage regulator.

Now lets look at the PLL chip. We will need to carefully disconnect pin 5 on this chip, as this pin sends out the 67 MHz frequency that the CPU runs off of. Now that we have our 67 MHz frequency disconnected, you may want to hook up the Playstation and verify that the CPU is not getting a signal. The Playstation should NOT boot. Once you have verified this, continue on.

Next we need to prepare our oscillator by running a 5V power source and GND to the appropriate pins. A suitable GND for our oscillator is not hard to find, I will usually hook up my ground to a screw that holds down the RF shielding. As for our power source, we will need to pull +5V from the voltage regulator. Now that we have the oscillator properly installed, we need to run our new clock signal on the CPU. This is where it can get tricky, as you will need to raise pin 4 on the Playstation's CPU and connect a wire from the oscillator's output pin to the CPU. The best way to raise this pin is to press a very fine-tipped soldering iron against pin 4. When this pin heats up, take your jeweler's screwdriver or x-acto knife, and carefully raise the pin. PLEASE double check to make sure no other pins are touching, or that your raised pin isn't touching the surrounding pins. These pins are very fragile, so I cannot stress enough the importance of practicing your soldering skills FIRST if you don't feel confident in doing this!

Once you have connected the output pin on the oscillator to Pin 4 on the CPU, double check all of your connections. Once you feel everything is installed properly, assemble, hook it up, and test! As always with overclocking, results may vary.

I hooked mine up and it works great! Since the CPU runs at a modest 40 MHz, you will not need to install any cooling devices. Doing so would be a waste of time and effort. Good luck with your overclocking!


This is a modified version of the original article written by Robert Ivy. A tutorial with photos can be seen at

All content on this page is ©2004, 2006 Underground Console Mods. This information can only be shared if credit is given to the respective creator; Robert Ivy

psx_overclock.txt · Last modified: 2019/08/27 20:45 (external edit)