Overclocking 486DX2

I have a old 66mhz AMD 486DX2 computer (stats in sig.) I have no idea if I should overclock it. Obviously I'll need to use jumpers on the motherboard, but I don't know which ones. I have no idea what model of motherboard it is, just that it was made by Digital Equipment Corp and has a SIS chipset.

So, does anyone have any idea of what I should look for on the jumpers, or would I most likely just fry the CPU if I tried overclocking it?

Oh, also, the CPU does have a small heatsink attached to it.

Find the manual on the mobo manufacturer's web site if there is one or look for it on the internet.

This would be for fun as I'm not sure you'd be able to feel the difference.

Most 486 motherboards came with options for 20, 25, 33, 40 and sometimes 50mhz bus speed. I had an SIS-chipset 486 motherboard that did very well, even worked at the rare and hard-to-accomplish 50mhz bus.

The AM486 chips were better overclockers than the Intels (in my opinion), you can likely get 80mhz stable (2 x 40 instead of 2 x 33) on that chip. You MIGHT be able to get 100mhz stable if you did some work or tried overvolting it, as there were some boards out there with differing voltage options last I recall.

iI think it would be fun to voltmod an old 486 board -- feed the processor 4v instead of 3.3v, and see if you could get an AM486/DX4 133 to be stable continuously at 200mhz. I had one that would do 200mhz (4 x 50) for short durations but was ultimately unstable; it would do 160mhz (4 x 40) reliably though.

I am not sure why one would want to OC a 486 when you can buy a faster processor that would go in that slot for a dollar on ebay.

Are you just bored and in the mood to tinker?

I wish I could find a manual for this board. I've looked all over it for a model number, but nothing I type into Google is helpful. I guess I'll look for jumpers with things like 20, 33, or 40 next to them. Thanks guys.

Oh, yeah, I'm just bored and tinkering with this.

MRD said:

I am not sure why one would want to OC a 486 when you can buy a faster processor that would go in that slot for a dollar on ebay.

Are you just bored and in the mood to tinker?

Click to expand...

Why not? I've recently aquired a PowerMac 7200 that I'm going to try to overclock. It has an awesome PPC 601 CPU at an exciting 90MHz. It looks like I'm going to have replace an oscilator on the mobo to oc it (none o' those wimpy jumpers for me). My point is, I haven't the slightest clue why I want to do this, but I'm going to anyway. It's fun...

I think...

edit:
Often jumper settings will be printed somewhere on the motherboard. Look all over for a table detailing jumper positions.

you might not be able to change the FSB...
it must be hard coded into the board...
if that is the case you are going to have to replace the quarts cyrstal that the clock is gernerated from.
They run at 2x the FSB...
So for a 33FSB board it will say 66MHz, and should be replaced with an 80MHz cystal... for a blazing fast 40MHz FSB