How latency numbers changes from 1990 to 2020.

What is Latency

In computing,"latency" describes some type of delay. It typically refers to delays in transmitting or processing data, which can be caused by a wide variety of reasons.

Note: 1 ns = 1 * 10^-9 sec

In 1990:

• L1 cache reference: 181 ns
• L2 cache reference: 784 ns
• Branch mispredict: 603 ns
• Main memory reference: 207 ns
• Compress 1K bytes with Zippy: 362,000 ns
• Send 2K bytes over commodity network: 1448 ns
• Read 1 MB sequentially from memory: 3038000 ns
• Round trip within same datacenter: 500,000 ns
• Disk seek: 20,000,000 ns
• Read 1 MB sequentially from disk: 640,000,000 ns
• Read 1 MB sequentially from SSD: 50,000,000 ns

In 2000:

• L1 cache reference: 6 ns
• L2 cache reference: 25 ns
• Branch mispredict: 19 ns
• Mutex lock/unlock: 94 ns
• Main memory reference: 100 ns
• Compress 1K bytes with Zippy: 11,000 ns
• Send 2K bytes over commodity network: 45,000 ns
• Read 1 MB sequentially from memory: 301,000 ns
• Round trip within same datacenter: 500,000 ns
• Disk seek: 10,000,000 ns
• Read 1 MB sequentially from disk: 20,000,000 ns
• Read 1 MB sequentially from SSD: 5,000,000 ns

In 2010:

• L1 cache reference: 1 ns
• L2 cache reference: 4 ns
• Branch mispredict: 3 ns
• Mutex lock/unlock: 17 ns
• Main memory reference: 100 ns
• Compress 1K bytes with Zippy: 2000 ns
• Send 2K bytes over commodity network: 1000 ns
• Read 1 MB sequentially from memory: 30,000 ns
• Round trip within same datacenter: 500,000 ns
• Disk seek: 5,000,000 ns
• Read 1 MB sequentially from disk: 3,000,000 ns
• Read 1 MB sequentially from SSD: 494,000 ns

In 2020:

• L1 cache reference: 1 ns
• L2 cache reference: 4 ns
• Branch mispredict: 3 ns
• Mutex lock/unlock: 17 ns
• Main memory reference: 100 ns
• Compress 1K bytes with Zippy: 2000 ns
• Send 2K bytes over commodity network: 44 ns
• Read 1 MB sequentially from memory: 3000 ns
• Round trip within same datacenter: 500,000 ns
• Disk seek: 2,000,000 ns
• Read 1 MB sequentially from disk: 825,000 ns
• Read 1 MB sequentially from SSD: 49000 ns

Comparison of Cache Sizes