3 ms·
> You also need to increase voltage if you want to increase clock speed. Or use lower VT cells (they turn "on" quicker), at the expense of increased leakage po
by kingosticks 9y ago
> You also need to increase voltage if you want to increase clock speed.
Or use lower VT cells (they turn "on" quicker), at the expense of increased leakage power. But at these geometries, faster clock speeds is getting less feasible and you need to find increased performance in other ways.
No logic signal needs to cross the entire die in one clock cycle, there is always an alternate design. For that reason, only registers 'talking' to each other need to see a clock at the same time, and even then there is a window. Clock routing is a consideration that takes resources but it's not a problem. Realistically, a logical signal won't be going anywhere remotely near 50mm at 3GHz in 10nm, so the clock doesn't need to either.
Max die size is also limited by the vendor's tooling i.e. what their machines can literally handle. And also physical issues such as warpage. If you make a massive die and it heats up in a non-uniform manner (different bits of it get hot at different times), it expands in a non-uniform manner. This can lead to all kinds of problems.
Chips stuffed full of memory will yield better than a logic-heavy chip since large SRAMs always now include redundancy. So this too has an impact on how big you can go for a given cost. You can however get registers that are built of multiple storage elements, the output value of which is the consensus. Don't know how much these get used.
- Nokinside 9y agoNumbers I mentioned are just physical maxims. In reality its the signal speed relative to jitter, time interval errors and data setup times that complicate the design and signal integrity. If the clock is 3GHz, the margin of error is the fraction of the time of the clock rate. You need to divide the chip into clock regions and add local cache for each core because fetching data far away is too slow.
- kingosticks 9y agoSure, but that's all independent of the size of the chip.