When you think of high-performance CPUs, you probably think about how we've shrunk transistors
over the years to the point where we can fit an insane number of them onto just one chip.
But did you know that the substrate the processor die sits on is also very important?
Not only do substrates give the delicate die structural support,
they also carry signals and connect the die to other parts of the system.
On most CPUs, the substrate is primarily made from epoxy and fiberglass,
that's plastic reinforced with woven glass fibers. But Intel is moving towards using substrates that are based on refined glass instead.
It's more like what you picture when you think of glass, like actual glass.
These glass core substrates have advantages that can allow for higher performance than the current
fiberglass and epoxy organic substrates that have served us well since the early 2000s.
One big one is how glass substrates react to heat.
Because chips are often heating up and cooling down as different kinds of workloads are put on them,
organic substrates stretch and relax in unpredictable ways.
Actual glass is stiffer and a lot more resistant to thermal warping.
This extra stability means you can put more routing holes in the substrate for extra power
and data connections, not to mention better signal integrity,
which is increasingly challenging as our transistors become smaller and smaller,
no matter what we do to stop them. For a practical example, think about how top-end server processors suck down hundreds
of watts of power, but run at only around one volt.
If you remember your high school physics, this means you're having to push through
lots of current at one time, which is pretty inefficient and leads to some of that power
getting lost. Because glass is more stable than organic substrates at higher temperatures,
you can put in a greater number of data and power connections,
which improves both signal integrity and power efficiency.
It's a pretty cool feat of engineering, but what does this actually mean for you,
the average computer enjoyer? Part of the reason Intel is so concerned about power efficiency and signal integrity
is due to how much electricity and data goes through data centers that do lots of AI processing.
And since most of us use some kind of cloud AI service these days,
switching CPU substrates is one of several developments that will help ensure our AI
capacity can continue to grow. In fact, the new substrates lead to a theoretical doubling of the data rate between two chips
in a data center, and will even help with communication between chiplets on the same
package due to allowing smaller distances between the bumps that connect the substrate to the die.
Glass is also easier to flatten out than organic substrates,
which makes manufacturing significantly simpler. And combined with the advantages we've already discussed,
chip makers should end up being able to put more processing dies on one chip,
as well as make those dies larger, giving us more compute power per package.
Just getting better and better. But are glass substrates also going to be coming to the CPUs we have at our home PCs?
The short answer is yes, but we may be in for a bit of a wait,
as the limitations that glass substrates are meant to address
are more of a concern for data centers right now. Intel is looking at rolling out data center chips with the new substrates in the second
half of this decade, while we'll likely see consumer chips towards the end of the decade.
Until then though, there's nothing wrong with using fiberglass. I mean, it's good enough for surfboards.
Hey, what are you doing here at the end of the video?
You rascal. Hey, thanks for watching.
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