Here’s how it works with the MDD. The motherboard bus speed is controlled by a resistor setting on the motherboard. With a 133mhz motherboards it's possible some components may be pushed a little when you up the bus speed. I’ve only personally upped the bus speed on a couple of MDD motherboards. With them there was no difficulty with the speedup. Someone i know has been using a speeded up motherboard for around 8 years if I remember correctly.
As to CPU speed, a resistor setting on the processor card governs it’s speed. That resistor setting has the cpu running at so many times the bus speed. For example 1.25 ghz cpu on a 167mhz bus would be set to 7.5 times the bus speed. If you were to move that processor card over to a MDD with a 133mhz bus then that cpu would then be running at 1ghz. However if you changed the resistor setting to 9.5 times then it would run at a little over 1.25ghz on the 133mhz bus. Changing those resistor setting is also how you do overclocking on the MDD.
Another factor in moving to a faster motherboard is RAM. Sometimes MDDs with slow bus speeds contained slower RAM. But RAM is pretty cheap nowadays if you need it.
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