Intel Pentium 4
Not much known about this CPU but it might be the first S423 CPU out there! Unfortunatly it does not work so it's all guessing what it would be.
Using my home and kitchen plate I measured a 39 gram for this CPU. It's brother QT69ES, a newer working sample, was 40 gram. The difference might be smaller then 1 gram as the plate is not that precise. Despite that it's safe to assume this CPU has the guts and thus a Willamette core in it.
The CPU fits easily along in the socket but doesn't get warm. Neither the board seems to be able to do anything with the CPU. The indicator leds on the MSI 850 Pro2 stay red instead of turning into green.
The CPU has very few markings on the heatspreader. This makes it difficult to name it (there is no sSpec number for example). On the heatspreader I only read 'D9356087' and '0090' along with an indentifier pattern.