The absolute numbers below will change as technology progresses but the relative numbers should stay the same.
According to LMAX the relative cost of locks and CAS is as follows (May 2011):-
| Operation (500 million times) | Cost (ms) | Relative Cost |
| Single thread | 300 | 1 |
| Single thread with lock | 10000 | 33 |
| Two threads with lock | 224000 | 747 |
| Single thread with CAS | 5700 | 19 |
| Two threads with CAS | 30000 | 100 |
| Single thread with volatile write | 4700 | 16 |
And according to Pinku Surana (Handwaving), here are the numbers for memory access (Jan 2009):-
| Operation | Cost (ns) | Relative Cost |
| L1 cache reference | 0.5 | 1 |
| Branch mispredict | 5 | 10 |
| L2 cache reference | 7 | 14 |
| Mutex lock/unlock | 100 | 200 |
| Main memory reference | 100 | 200 |
| Compress 1K bytes with Zippy | 10,000 | 20,000 |
| Send 2K bytes over 1 Gbps network | 20,000 | 40,000 |
| Read 1 MB sequentially from memory | 250,000 | 500,000 |
| Round trip within same datacenter | 500,000 | 1,000,000 |
| Disk seek | 10,000,000 | 20,000,000 |
| Read 1 MB sequentially from network | 10,000,000 | 20,000,000 |
| Read 1 MB sequentially from disk | 30,000,000 | 60,000,000 |
| Send packet CA->Netherlands->CA | 150,000,000 | 300,000,000 |