Update:
from Intel's website
Intel® PD440FX Motherboard
Processors Supported
The motherboard only supports Pentium® II processors that run internally at 233, 266, 300 and 333 MHz and have a 512KB L2 cache supporting ECC or non-ECC operation.
Special instructions must be observed when using 333 MHz Pentium II processors.
While the Intel® Celeron™ processor uses the same P6 microarchitecture as the Pentium II processor, but there are some differences. No qualification or compatibility testing has been performed using the Celeron processor and the BIOS does not contain support for this processor. No additional BIOS upgrades are planned for the PD440FX motherboard. While the Celeron processor may appear to work in a PD440FX board, the reliability of operation is not known.
Warning: Processors not specifically listed by type and rated speed may have requirements that are not supported by the motherboard's design. Use of unsupported processors may result in improper operation, damage to the motherboard or processor, or reduced product life.