Well every review I've read said that people couldn't get past the 'infamous 215FSB barrier' and upon doing this mod allowed them to gain another 10FSB. I think it was my RAM that was hurting me cause it just got fried last night which caused a corrupt file in my HD because of the restarts which caused a format, but now I'm running at 2.6GHz 13x200 at 1.925 Vcore and it's prime95 stable for 10 hours so I know it's stable...computer wouldn't do that with my 512mb RAM that was in here before so that probably had something to do with it. I'm reluctant to take off the heatsink cause I just put it on two weeks ago with AS5 and I have yet to leave a heatsink on long enough for the AS5 to completely settle.
Does it only apply to mobile chips or can i do it with my XP 2400+?
It is mainly for mobiles, but it will indeed work for your 2400+ XP....I also have the 2400+ XP, yes that's right, my main computer (the one I'm writing on now) has the 35w 2400+ XP-M while my secondary machine in my room has the 2400+ XP lol. This mod does indeed unlock the chip to 166FSB with only one wire used and 200FSB with two wires used.....remember though you'd want to also clear your CMOS when you did this because you'd then be trying to boot up your 2400+ at 15x200 since it's default is 15....if you clear the CMOS with the newly opened multiplier it should default to like.....6 multiplier or something of that sort.
The 2400+ XP is supposedly a good overclocker (I read this quite some time ago) but it's the multiplier lockage that really stops it. Some chips are old enough to already have an unlocked multiplier, usually before week39...yours probably isn't unless you've had that CPU for a long ass time. And the only way to check the week is to look at the sticker on the CPU itself. They also sell whats called 'Speed Strips' That basically wires the pins for you. a Piece of paper that fits around a certain section of pins and 'jumps' them if you will to unlock the multiplier. Read about it here:
http://www.speed-strip.com/over.htm
If you read at the bottom they used a 2400+ XP for testing. I was actually thinking of getting that strip. They say upon using the strip and rebooting it defaulted to the lowest multi of 6 which means the strip is working.
ak_smallz.....click that link I provided at the very top..the second link...that shows you where to put the copper wire in the socket holes....this is the same thing as the speed strip...the speed strip fits around the pins to hold onto something, but at the same time it has tiny wiring to connect two of the pins on your CPU...when you put a U-Shape copper wire into the socket holes like the image demonstrates, this is doing the same thing...electricity from one pin hits the other and causes the right connection...so the principle is the same...it works in the same fashion...someone just made up the 'Speed Strip' to make it easier on some people and obviously for money reasons. Any Thoroughbread or Barton core will work with the speed strip so I'm pretty sure the L12 mod is based on the same principle.
EDIT: Not that this needs to be any longer, but at the top of the SPEED STRIP page it tells you that the newer XP's can no longer be unlocked with this method. And an article also explains why this is and that no wire trick, bridge trick or anything like that can unlock these multipliers because they are coming out factory locked. You can read the article here:
http://www.ocforums.com/showthread.php?threadid=244237
Then you have to see if you have the steppings that could still be unlocked. So if your 2400+ XP is early enough you can unlock the multi, if it's not I'm not sure if you can, but you could still try the L12 mod anyway. I might just have to do it on my secondary.