> while also being non-volatile

For something like a cache on a CPU (the main use of SRAM), what's the purpose of it being non-volatile? SRAM doesn't need refreshing, and it's a relatively small percentage of total power.

It may be a small percentage of total power at full load but what about at idle? Modern CPUs try to optimize power usage by remaining idle as much as possible. When idle, power usage is roughly in proportion to die area fraction. Since caches have been getting larger and larger this would represent a larger fraction of total power at idle.

> For something like a cache on a CPU (the main use of SRAM), what's the purpose of it being non-volatile? SRAM doesn't need refreshing, and it's a relatively small percentage of total power.

It sounds like it would be chosen for other reasons, and there would no purpose for the non-volitiliy beyond it being a nice-to-have in some weird scenarios.

Sort of like using core as main memory. That was just the main memory technology of its day, it happened to be non-volatile, but that wasn't it's main selling point.

Less power is still better. Also, if we have to solve the SRAM scaling problem with 3D chip stacking, this will be an issue.

It's also even more expensive. As if the upcoming nodes weren't already ridiculous in that respect.

It would be very useful in combination with NVRAM main memory since you no longer have to deal with crash consistency issues arising from your cache being wiped on a reboot.

What's the point of reboot, if not to reset state?

Poorly worded on my part, I simply meant restart after a crash.

Good luck making the next step of memory miniaturization with a magnetic technology.

There's a reason magnetics were popular when circuits where finger-sized, and completely disappeared when they got smaller. It may not be impossible to make 3D magnetic circuits that match 2D electronic ones, but it's very close to that.

These things are more accurate called "spintronics." They are very different from conventional magnetic recording technologies.

Having worked closely on the circuit side of things with folks doing research on spintronics and STT-MRAM devices: it’s going to be a very long time still before this can replace embedded SRAM. The MRAM itself can be made quite small, but you still need an access transistor and wrote currents are still too high, which means very big transistors, which then dominate memory area… Also, writing is much slower compared to SRAM.

It’s a very nice embedded flash replacement though…

It might be SOT-MRAM over STT-MRAM. I'm of the impression that SOT-MRAM doesn't have the slow write problem.

What happens if i put a magnet nearby ? Does it still work ?

I have high hopes for spintronics on the power efficiency front, but for miniaturization, they are as much of a hassle as any other magnetic technology.

These will not replace SRAM in leading process nodes. Some microcontrollers will use MRAM as a unified SRAM/Flash memory space, but that will probably be all.

MRAM is faster than DRAM. It can do more than that. It has a real chance of filling the gap between SRAM and DRAM, possible replacing SRAM where density is needed.