3 ms·
>L3 as big as main memory That's not possible for many a reason, caches on the CPU die (or substrate, think AMD) tend to use the infamous 6 transistors per bit
by xxs 3y ago
>L3 as big as main memory
That's not possible for many a reason, caches on the CPU die (or substrate, think AMD) tend to use the infamous 6 transistors per bit. The ones in the RAM are composed of a single transistor + capacitor, much denser. We can't have more L3 as the latency to access would pretty much make it main memory. The cache are as big as they can be, increasing their size overall doesn't contribute significant performance boost.
The hardware bill is just not a thing, it's physically impossible to build very large caches that have low latency.
- tankenmate 3y agoThere are CPUs that have external (including L3) caches; and yes, off die they will have a lower latency. And that is not to mention that a cache topology uses much more power, and not just in the T6 cell itself, there's all the cache handling logic as well. But, it is possible to do; insane but possible.