https://www.techpowerup.com/288153/galaxy-shows-off-first-ddr5-aida64-memory-benchmarks Remember the "Lego"/"Tetris" DRAM modules that
Galaxy was showing off last week? Well, now we have the first benchmarks of said memory running at 4,800 MHz/MT/s with standard timings of 36-36-36-76 and the results are pretty much in line with DDR4 at the same clocks, but with a CAS latency of 19. That said, this doesn't take the latency into account and this is where the issue lies, just as expected.
Despite the change in memory architecture by going to a dual 32-bit bus per DIMM, instead of a 64-bit bus, there is somewhat surprisingly no real gains to be had in AIDA64, even when using two DIMMs. Earlier AIDA64 DDR5 memory benchmarks have only been with a single DIMM, so it has been a bit hard to compare the performance. However, the latency is up by about 30 ns compared to equivalent speed DDR4 memory, which is quite a jump. This does admittedly happen every time there's a transition to a new DRAM technology, but the increase in memory latency has never been this high before. Hopefully RAM with tighter timings and improved CPU memory controllers will help reduce the latency over time, since it'll have an adverse affect on a lot of things, least not many games.
As I personally expected DDR5 memory isn't going to make a difference over DDR4 until you get to speeds of 6400 MHz and over.