From a system architecture standpoint, the LPC clock is not used for anything except the Low Pin Count bus. As such, we could conclude that since there are no connections to the LPC clock or the other pins of the bus, that it’s not needed.
There is a remote possibility that it could still be needed though. If the bios tries to query to see what might be present on the LPC bus, the clock could be a problem. It all depends on how Intel designed this I/O. If they have a driver circuit that sends the clock out continuously and the bios decides to look for one thing or another on the LPC bus, if circuit is designed to loop back the clock directly from the pin to internal circuitry, that needs to see it, then that could cause a hang condition. That is, assuming that the LPC clock pin driver has degraded sufficiently.
The fix of course, barring reprogramming the bios to not go anywhere near the LPC, would be to install a pull-up resistor on the circuit board. Unfortunately, this is well nigh to impossible on the DL4100 or DL2100 since there are no traces from the LPC clock pin. There is certainly a copper pad that the pin is soldered to, but no actual traces. You’d have to remove the CPU and somehow add a rework wire to a pull-up resistor. If you’re going go to the trouble of removing the CPU, you should just replace it with a later stepping of the CPU where this issue is fixed. Alternatively, if you’re really good and can locate the precise coordinates of the pin from the other side of the circuit board, you might be able to drill a hole straight down until you hit solder and then somehow attach a wire to a pull-up resistor. I might try that for a laugh, if either of my DL4100s goes down.
It was much easier to add the pull-up resistor to my 2 DX4200s since there are traces from the LPC clock pin on the DX4200s.
Keep in mind that I’m only speculating as to the possibility of the CPU needing the LPC clock looped back from the pin itself. I don’t actually know if it does or does not. Intel could probably tell us, but they don’t seem to want to talk about it.