No. They use different connectors, different rules to activate and refresh the stored values, and different voltages, so even if someone could make a physicall adapter, they still would not work. DDR3 use a 240 pin connector. DDR4 use a 288 pin connector (not 260). [Source1][1] [Source 2][2] [Micron data sheet][3] [1]: https://www.wepc.com/reviews/ddr3-vs-ddr4/ [2]: https://www.bestsevenreviews.com/ddr3-vs-ddr4/ [3]: https://www.micron.com/-/media/client/global/documents/products/data-sheet/modules/unbuffered_dimm/ddr4/asf9c512x72az.pdf