First post, by feltel
I'm about to build a new rig based on an MSI 5128 v1.1 Socket 7 board and an MMX CPU. I currently have an Pentium MMX 200 SL27J which I want to run at 133 MHz to have it passivly cooled. If I set the switches according to the PCB printing I get weird results.
The board has a row of dip switches which set the FSB and the multiplier. See https://retronn.de/imports/hwgal/hw_mainboard … 5128_430hx.html
Setting it to 133 MHz results in an 166 MHz on BIOS boot. So the CPU runs at 2.5 * 66 vs. 2.0 * 66. Setting it to 75 Mhz (i.e. 1.5 * 50) make this CPU run a 125 MHz. The MMX seems to interpret 2.0-settings as 2.5 and 1.5 as 2.5 also. It seems my CPU has a fixed multiplier and can only be downclocked by lowering the FSB. Am I correct?
Dont want to run it at such a low FSB as it should hit performance on a great level.
Does non-fixed MMX exist?