walsufnir said:
What is it for? Well, the "path" from and to cpu is "long" and slow - that's why we have caches in processors so that often needed data are "nearer" and faster accessable to the cpu. We now also have 2nd-level-cache, sometimes 3rd-level-cache, and then ram. You can think of another cache-like memory between the cpu and ram - esram is an especially high bandwidth, low-latency memory-solution. Look at this picture:
From high to low memory is increased but therefore speed is also decreased - think of esram between ram and the caches. |
... don't give out false information please.
eSRAM => Embedded Static Random Access Memory.
In the pyramid, it is the 'Physical memory'.. its NOT a cache thats 'nearer' or 'further' from the CPU.
/facepalm
So what exactly is the problem here?
http://www.differencebetween.net/technology/difference-between-sram-and-dram/
1. SRAM comes in smaller size (You don't have 4gb of sram like you do with DRAMs) . So microsoft needs to put an 'array' of them to match the amount of memory needed
2. SRAM cost more transitors. DRAM only takes 1 transistor per bit, SRAM takes 6.
3. More transistor = more heat.
4. More heat = more errors
5. To dial down the heat issue, they reduce the speed.
Other issues:
More transistors = lower die yield = more expensive to produce.
