I have about 8 or 10 DDR-2 and 6 DDR-3 modules which I don't really need any more. I wonder whether there's a 5.25" SATA hard disk drive that takes DDR RAM (you can recommend for DDR-2 or DDR-3).
From the size of a 5.25" drive I'd estimate that it could have ~10 slots but 8 would also be ok, so it would be able to be a 16 GB to 20 GB disk.
From the performance, it should be able to outperform an SSD when it comes to writing speed, i.e. it should be higher than 500 MB/s.
The price should not exceed 35 €.