http://nfggames.com/forum/index.php?showtopic=2220QUOTE :
I had a spare slimline PS2 that was donated for this purpose, so it was time to get started.
Examining the board, I noticed several crystals (about 8 or 9) on the motherboard providing different clock signals for different functions, but one stood out to me that was right next to the CPU: ~18 MHz. This oscillator is not labelled and the speed was determined by probing the signal with an oscilloscope.
The PS2's CPU runs at 294 MHz, with the GPU operating at exactly half this speed. My fear was that the GPU and CPU would share the same clock signal, but I had to test this to confirm it.
18 x 16 = 294. This was too much of a coincidence for me to pass up, it was time to heat up the soldering iron and pull out a 21 MHz crystal for installation.
After desoldering the original 18 MHz crystal and installing a 21 MHz crystal I reassembled the PS2 and turned it on. My fears were confirmed; the GPU and CPU were both running overclocked; with the CPU running at
343 MHz and the GPU running at 171 MHz. Overclocking the GPU causes the screen to roll, since it it outputting a fequency greater than 60Hz which most TVs cant handle.
Turns out the PS2 is impossible to overclock without causing problems with most standard TVs. The GPU takes the 18 MHz signal, multiplies it by 8 internally, and outputs the signal to the CPU. The CPU takes the GPUs internal clock speed and multiplies it by 2 internally, resulting in a 294 MHz clock speed. It wasn't successful, but I thought some of you might be curious. Cheers!
ce' que je disais ya des barges
Message édité par poulpito le mercredi 28 mars 2007 à 13:08:04
