Demand for DDR3 is up because people who want DDR5 or DDR4 but can't afford either any more are choosing DDR3 and old DDR3-compatible systems to put it in, instead of what they really want.

All memory products use many shared resources in the supply chain, so if there is high demand in one product line, others have to raise prices to compete for the resources or stop making those lines altogether.

That is to say at least you were able to buy them at $350 today, with the current trajectory there will be no supply at all in few months.

Being desperate?