Hacker News Reader

What happened to SRAM ?

Still in wide use in CPU caches. It does not scale well to smaller sizes, and inherently requires more transistors than DRAM, which means it's not cost-effective for main memory.

I forgot were I saw it but it was an analysis of cache to die size and how it has effectively stopped scaling. Larger cache just means larger chips now.

It sort of makes sense because SRAM cannot have the same transient nature of a calculations transistor. It has to hold the state for longer than one 3 billionth of a second. So it has to be a little more robust.

This is my intuitive take so it could be completely wrong.

The densest kind of SRAM has stopped scaling. However, it's instructive to compare the size of the L3 on AMD Zen4 and Zen5 dies. There is still at least some scaling to be had for SRAM that's built to be fast.

(Of course, this is still very irrelevant for comparison to DRAM; the price difference is huge.)

Probably on Asianometry: https://www.youtube.com/watch?v=2G4_RZo41Zw

It's huge compared to DRAM. It's worth making a few megabytes of SRAM per core, but not a lot more than that.

Reply on news.ycombinator.com