I found a damaged i9-12900K listed for $120–$170 less than comparable working chips. The seller says the CPU boots, but only the B2 memory slot or channel works after inserting a faulty memory stick into three slots. They claim there is no visible CPU damage and that the problem is internal.
I asked whether they tested multiple known-good memory kits, boards, and the CPU socket, but their answers were vague. My current system uses a 12400F with 4x8GB DDR4-3200, and I was considering this as a final upgrade for the next three to five years. If I bought it, I would probably run one 16GB or 32GB DIMM in the working slot rather than reuse all four sticks.
Is this a sensible gamble, or are the savings too small for a CPU with suspected memory problems? Can a faulty DIMM actually damage a CPU memory channel, and could the seller simply be misunderstanding a motherboard, socket-pressure, or DIMM-slot issue?
3 Answers
A bad DIMM can potentially damage hardware, but it is not a normal or convincing explanation for exactly three CPU memory channels failing. A faulty board or socket contact is at least as plausible, and the only way to separate those possibilities is to test the CPU in a known-good board with multiple confirmed-working DIMMs. Even then, you would still be accepting a used chip with a history of electrical failure and little useful warranty coverage. A working 12900K is the better choice for a long-term upgrade.
I would pass. A dead memory channel is not realistically repairable, and the seller's explanation is questionable. Even if the chip works today, there is no way to know whether the damage could worsen. Saving $120–$170 is not much compensation for buying a processor that may become unusable or leave you stuck with single-channel memory.
That makes sense. I had assumed a damaged channel would simply remain in the same condition, but the possibility of progressive failure makes the gamble much less attractive.
The 12900K has two memory channels, not four. The four DIMM slots are normally split between those two channels, so a report that three slots are dead does not line up cleanly with a single failed CPU channel. It could be a motherboard, socket-contact, mounting-pressure, training, or testing problem instead. The seller does not sound confident enough in the diagnosis to justify the risk.
That was my concern too. On these boards, the slot wiring and daisy-chain behavior can make a slot appear unusable depending on which other slot is populated, so I doubt the seller tested the CPU thoroughly with known-good parts.
I was tempted to buy it because the purchase could be returned if it failed immediately, but that still leaves the risk of intermittent problems or a chip that deteriorates later. The consensus is probably right that the discount is not enough.