What's the catch with FRAM?

If some (insert semiconductor corporation) develops a process of increasing the density of FRAM, it could replace DRAM. While marginally slower than SRAM, this could upend the DRAM industry for being a cheaper, more performant alternative to our main memory in PC's, DRAM.

Considering the widening CPU to Memory Speed/Bandwidth gap problem - FRAM as I see it developed in competition directly with DRAM - is solved. It also uses the least amount of power of all memories, which means for the same volume we can extract more "power/speed" or potentially "capacity".

Also - FRAM has the highest endurance of all memories (Flash, EEPROM, etc) in a NVM (Non-Volatile Memory) use case. By an order of magnitude. I believe a few orders of magnitude really!

In a volatile use case, the destructive reads are irrelevant. Data retention is guaranteed for years and years when they quote the endurance of the NVM memories. What about the potential need for retention to only be milliseconds or less?

There is no catch!

FRAM is great, however, the technology has destructive reads. Flash technology has a limited write/erase cycles, but the reading cycles are almost unlimited.

In FRAM, each read cycle actually affects the memory and it starts to degrade. TI states that they've found the FRAM has "Wear-out free endurance to 5.4 × 10^13 cycles and data retention equivalent of 10 years at 85°C". After some calculations this turns out to be around 2 years of constant read cycles or so (without taking into account ECC).

The reality is that for most low power applications, where duty cycles are low, this is not an issue. You will need to evaluate it for your specific application.

The limit in speed is also present, so waitstates will be added if needed. However, one solution is to load code to RAM, run it from there (avoiding the cycles on the FRAM) and avoiding the speed limit.

There was an E2E post on the topic here that discussed some of the ramifications.

A good App Note from TI about what the advantages of FRAM are as far as security is Here

The only real issue with FRAM is that for the really dense parts, the part of the market that drives volume and margin, they cannot yet compete on density (which is either a yield thing or a size thing - it doesn't really matter which). For the smaller parts (i.e. competing against older version of same technology) they do well.

So yes, it's a good fit for experimentation as long as you stay in the same size parts.