You can't.......you need a new Motherboard.......
the ASUS A7V Motherboard was only designed for 100MHz FSB AMD Processor's...so that means AMD Athlon T-Bird Type 'B' which is what you had (your 800) or AMD Duron 600 - 950MHz Processors. Your new 1.4GHz T-Bird is a Type 'C' which uses a 133MHz FSB, and the Via KT133 Chipset does NOT support a 133MHz FSB (regardless that your BIOS will Allow it, it wont work.....
Therefore you Only have 2 options........
1) Take your processor out of the board.....grap a SHARP Pencil......and fill in all 4 L1 bridges (connect them) so that they look like this: | | | |
If they already look like that than your lucky, you dont need to pencil them in, but if they look like this: : : : :
than you will have to pencil it in........
After you do that, Look in the Motherboard Manual for the Dip Switches settings....you have to put your computer in JUMPER Mode........THAN put the dip switches according to what the Motherboard Manual says for Multiplier # 14.0...THAN your CPU will work at 1400MHz but at a Bus speed of 100MHz WHEN it is Intended to run at a Bus speed of 133MHz..
2) Buy a new motherboard (the best thing to do) as you will be able to PROPERLY Utilize your Processor witht he full speed capability AND you will have a newer motherboard which in-hence will be MUCH faster than the old ASUS A7V.
Good Luck...
-MeTaL RoCkEr
<A HREF="http://www.anandtech.com/mysystemrig.html?id=13597" target="_new"> <b> My Rig </b> </A>