from Hacker News

A possible answer lies in the following table, which illustrates typical computer actions and their speeds. It also shows how long these actions would take if performed by humans:

  Action                     CPU Time       Human Time (Comparison)
  ------------------------------------------------------------------
  Addition                  0.5 ns         10 seconds
  Multiplication            1 ns           20 seconds
  Division                  2 ns           40 seconds
  Cache Access (L1)         0.5 ns         10 seconds
  Cache Access (L3)         5 ns           1 minute
  RAM Access                50 ns          10 minutes
  Disk Access (NVMe SSD)    10 µs          33 hours
  Disk Access (SATA SSD)    100 µs         14 days
  Disk Access (HDD)         10 ms          4 years
  Ping (Website, 50 ms)     50 ms          20 years
  Application Start         2 s            1,000 years
  4K Image at 60 Hz         16.7 ms        7,000 years

Modern processors, such as the Intel Core i7, are incredibly fast. A simple addition takes only 0.5 nanoseconds—an almost inconceivably short time compared to how long a human would need. But this speed is often bottlenecked by slow memory access:

Cache accesses (especially L1 and L3) are relatively fast, but RAM access is significantly slower.

Disk accesses, even with fast NVMe SSDs, are orders of magnitude slower compared to CPU speeds. An old HDD (spinning disk) is especially problematic.

Programs with high memory requirements can exacerbate these delays. The more data that needs to be loaded, the more frequently the RAM or disk is accessed, nullifying the CPU’s speed advantage.

2. The Bloat of Modern Software

Another factor is the sheer size of modern software. While older programs were lean and efficient, today’s applications are often “bloated” with numerous features and graphical interfaces. This program size has direct consequences:

More data needs to be loaded from the disk.

Larger memory requirements lead to more frequent RAM access.

Example: A text editor from the past was only a few megabytes and could load in milliseconds. Modern editors with cloud integration and advanced features are often hundreds of megabytes and take seconds or even minutes to become fully operational.

3. Network Dependency and Updates

Many modern programs check for updates at startup or load online resources, which can significantly delay their launch:

A ping to a website takes about 50 milliseconds, a relatively long time compared to CPU operations.

Update checks can take several seconds or even minutes, especially on slow internet connections.

Older software was often offline and ran without delay, while today, a large portion of computational resources is spent on server communication.

4. Conclusion: Speed Is Relative

The speed of modern computers is influenced by multiple factors. Despite faster processors, modern PCs often feel slower because:

Memory access (RAM and disk) bottlenecks the CPU.

Software has become larger and more memory-intensive.

Network operations, such as update checks, delay program launches.

If your new PC feels sluggish, consider these bottleneck factors. Optimizing memory usage, reducing unnecessary background processes, and using lightweight software can significantly improve perceived speed.

Note: The times listed above can vary significantly depending on the specific CPU, GPU, or hardware configuration.