Hello! Can anyone advise me on how to get this CPU running at 300MHz on this board? I've found the undocumented jumper settings for 2.2V on a Google Groups thread but there doesn't appear to be the ability to get a 4.5 clock multiplier. I know that some CPUs will upscale a lower setting i.e. 2x as 6x but that looks like it's only for integers. The CPU does work but only at 233MHz so far. Thanks
The motherboard does not appear to have a setting for the BF2 signal which is the third bit to set multiplier, the 2x/6x thing only works for CXT core K6-2 and doesn't need BF2. When BF2 is set, 2x becomes 4x, 2.5x becomes 4.5x, 3x becomes 5x and 3.5x becomes 5.5x.
The way to set BF2 on a motherboard that doesn't support it, is by a "socket trick", or modification to the CPU or motherboard.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
Ah OK, Thanks BitWrangler, I thought it might be a tricky one. Not to worry though as the PC was found in an old store room a few weeks ago. I have a few old Socket 7 cpus in a box and the K6 would have made a good upgrade from the Pentium MMX 233MHz fitted. The others are an IBM 6X86L PR200+ and a Pentium MMX 200MHz, making the AMD the cream of the crop...
Well I was trying to find a good reference for this, but google is useless and keeps insisting that I would rather know about BattleField2 so couldn't dig up what I wanted.
Anyway, I happened to have a motherboard nearby which also didn't have BF2 and I had previously used the "socket trick" on before, and marked the holes with a sharpie so I'd remember which holes it was. Basically, you take a strand of wire make it into a U shape and drop it between the two holes marked in black, this connects BF2 and enables the 4 to 5.5x multipliers for K6/K6-2/K6-3 and for Cyrix and IBM 6x86 which map some of them to different multipliers, and also for Winchip, which has a complete different set of multipliers I think. Intel MMX and Tillamook mobile use a different pin for higher multipliers and this will not work on them. May need to pluck the wire out with tweezers when/if you change back to Intel.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
This image of doing this with Socket A gives you a good idea of how small the wire you will need to use.
"I'd rather be rich than stupid" - Jack Handey
Yes the strands in wall voltage power cords etc are likely to be too fat. Some stranded wire from low voltage DC hookup cables or out of mangled headphone cord is probably best. Anything that's more than a third the size of the hole is definitely too big, gotta get the pin in there too without bending it, something around a fifth seems about right, though you can get some real fine hairlike strands, they have the disadvantage of getting stuffed down into the socket, breaking or otherwise getting lost somewhere you least want them.
Edit: though if some thin hairlike stuff is all you can find, you might be better off tying the pin on the CPU itself, take a long strand of it and wind it in a figure 8 round those 2 pins on the CPU, remembering that it will be a mirror image of the socket, and pack it down on there good with tweezers and make sure the ends aren't gonna pop out and short to another pin.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
Perfect, I'll have a rummage and see what I can find. I'll add my results to this thread when I get some time to have a fiddle. Many Thanks BitWrangler and Repo Man11
BitWrangler wrote on 2024-03-16, 16:57:Edit: though if some thin hairlike stuff is all you can find, you might be better off tying the pin on the CPU itself, take a long strand of it and wind it in a figure 8 round those 2 pins on the CPU, remembering that it will be a mirror image of the socket, and pack it down on there good with tweezers and make sure the ends aren't gonna pop out and short to another pin.
I found the method of wrapping the wire around the CPU pins very difficult, I had a thin wire that kept falling off because it was too soft to keep its shape when tightly bent around the pins. I also felt it could unwind later and cause a short circuit. After 20 minutes of trying I gave up and tried the socket method (dropping an U-shaped piece into the holes), that worked right away.
Right, so I've had a go and can confirm everything is working! I used a strand of wire from an old mains lead cut to a suitable length then dropped it in with some tweezers. I've included some photos and some CPU-Z screen grabs, in Image 2 the VID jumper block is set to 2.2V (red), Clock jumpers to 66MHz (green) and the multiplier block set to 2.5x which is registered as 4.5x (yellow). You can see where I've marked the BF2 pins in images 2 and 3 and the size of the wire strand used. Big thanks to everyone for their assistance and hopefully this will be useful to other people too. Cheers Seb
