The upcoming debut of the third-generation AMD Ryzen CPUs should give the system memory sector a breath of fresh air. These processors will continue to use dual channel DDR4 controllers, but they should be able to achieve higher frequencies than can now be achieved with on the market Ryzen processors.
Meanwhile, there is no shortage of new DDR4 solutions with increasing clock frequencies, with the Taiwanese G. Skill always presenting new solutions to Computex historically. A first example comes from this DDR4-5000 kit, which combines a very high frequency with pushed timings like those 17-17-17-37 that are typically used with much lower frequencies of the clock. The company also showed 5,200 MHz kits but intervened in this case on the timings that need to be more conservative in order to ensure stable operation. We don't know when these memories will be debuting on the market, but it's very likely that it will be accessible to most passionate users in the next few months for a cost in a dual kit configuration.
Special suggestions such as this Ripjaws memory kit are also available, with 12 32 GB modules each installed on an Intel platform with Xeon W-3175X processor. The total quantity in this case is 384 GB of memory, with a final 4GHz clock frequency with timings that are moderately conservative due to the total amount of integrated memory. A record for a workstation like this, not so much for gamers as for those who make very thorough use of video and photo content creation programs.