Asus A7V8X-X reads my AthlonXP200 as 1250mhz only

System:
Processor: Athlon XP 2000
Mobo: Asus A7V8X-X
PSU: 400 watts
CPU Fan: Ttake Volcano 9

problem is that when i set the cpu speed at 1667mhz, system freezes and i get a black screen. but when i set it to 1250mhz, system runs smoothly. i think theres a problem on my vcore voltage because @ +3.3 Voltage Settings it only reads 2.80V, like this:

MB Temperature: 40C/104F
CPU Temperature: 62C/143.5F

VCORE Voltage: 1.69V
+3.3V Voltage: 2.81V
+5V Voltage: 4.59V
+12V Voltage: 11.90V

i have to set it to "Ignore" option first before it boots.


options i have right now are:
- replace cpu fan
- update bios
- replace mobo

i need help right now and im running a little short on money to buy a new mobo
any suggestions will be greatly appreciated... thanks in advance...