10 ms·
L3 is almost never SRAM, it's usually eDRAM and clocked significantly lower than L1 or L2. (SRAM is prohibitively expensive to do at scale due to die area requ
by morei 5y ago
L3 is almost never SRAM, it's usually eDRAM and clocked significantly lower than L1 or L2.
(SRAM is prohibitively expensive to do at scale due to die area required).
Edit: Nope, I'm wrong. It's pretty much only Power that has this.
- dragontamer 5y agoAs far as I'm aware, IBM is one of the few chip-designers who have eDRAM capabilities. IBM has eDRAM on a number of chips in varying capacities, but... its difficult for me to think of Intel, AMD, Apple, ARM, or other chips that have eDRAM of any kind. Intel had one: the eDRAM "Crystalwell" chip, but that is seemingly a one-off and never attempted again. Even then, this was a 2nd die that was "glued" onto the main chip, and not like IBM's truly eDRAM (embedded into the same process).
- morei 5y agoYou're right. My bad. It's much less common than I'd thought. (Intel had it on a number of chips that included the Iron Pro Graphics across Haswell, Broadwell, Skylake etc)
- dragontamer 5y agoBut only the Iris Pro 5200 (codename: Crystalwell) had eDRAM. All other Iris Pro were just normal DDR4. EDIT: Oh, apparently there were smaller 64MB eDRAM on later chips, as you mentioned. Well, today I learned something.
- epmaybe 5y agoHa, I still use an intel 5775c in my home server!
- beebeepka 5y agoI think the chip you are talking about is Broadwell.
- dragontamer 5y agoBroadwell was the CPU-core. Crystalwell was the codename for the eDRAM that was grafted onto Broadwell. (EDIT: Apparently Haswell, but... yeah. Crystalwell + Haswell for eDRAM goodness)
- Unklejoe 5y agoL3 is SRAM on all AMD Ryzen chips that I'm aware of. I think it's the same with Intel too except for that one 5th gen chip.