Coincidence or common problem (with Socket A)

Scenario A: My friend has an Athlon Thunderbird 1.3Ghz A few months ago his motherboard died. He bought a new Foxcomm board to replace his dead board. The Foxcomm board had issues running the chip at 1.3Ghz. He thought the board was bad and RMAed it for another board. He had the same problem with the second Foxcomm until he set the chip to run at 1Ghz instead Since then, he hasn't had any problems.

Scenario B: My mother's motherboard also died earlier this year. I went and bought a new motherboard from a local shop. The CPU is an Athlon Thunderbird 1.2Ghz. I set the Bios up so the chip's clock speed is correct (1.2Ghz) but eventually the chip runs at 900Mhz (and I have to reset the setting in the Bios) The board is an ASRock board.

Is this a coincidence or do older Socket A chips not play well with newer Socket A boards. Both chips were purchased in May of 2001. Are the chips reaching towards the end of their lifespan and starting to die?

any input is appreciated (since it's a weird problem),
krfan1