The cost of leaving the CPU
One network trip is 300 million cache hits.
300,000,000×
That is not “a little slower.” It is the difference between one second and roughly nine and a half years.
Packet CA → Netherlands → CA
150 ms
300 million
9 years 6 months
Put it on a human clock
One network round trip lasts 9 years 6 months.
That comparison holds every ratio constant: one L1 cache reference becomes one second.
Three honest rulers
Every bar below is linear.
When a value nearly disappears, that is the lesson. Each ruler widens the field of view; the whole ruler above is marked as a hairline in the next one.
CPU & synchronization
Memory & compute
Storage
Network
1.5M×
What the zoom reveals
The widest ruler is 1.5 million times wider than the first.
And an L1 cache hit uses only half of one percent of that first ruler. Keep data close, batch distant work, and avoid serial round trips.