candle_86 wrote:But do we know if his motherboard supports spilt votage rails necessary for the Pentium MMX, early socket 7 boards did not.
The Pentium MMX do not need split voltage rails to function, it will run on a 3.3V Core/IO "STD" voltage spec just fine, at least on the motherboards I have tried but the "VRE" 3.5V-3.6V voltage spec is a bit too high for me to think its a good idea.
Overvolting do increase the power draw though but I bet a Pentium MMX 233 @ 3.3V still isnt worse than a stock K6 233 MHz (3.2V). Intel did not push the Pentium MMX because they diddnt have to.
If one really wants to play it safe neither a fast Overdrive with its own VRM or overvolting a Pentium MMX CPU is a good idea for an old Socket 5 motherboard. The point is that Im not sure one is worse than the other as I think both will draw about the same amount of power because of the power loss in the Overdrives VRM. What I am sure of is that it's easier to find a good cooling solution for the Pentium MMX that also cools the motherboard area around the CPU.
The Pentium MMX 166 and Pentium MMX 200 do not always support the 1.5x = 3.5x multiplier which can be an issue on old boards with only a single jumper for multipliers (1.5x and 2x).
New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.