Third Green500 list puts Big Blue way ahead.
IBM has once again dominated the Green500 list which ranks the world's supercomputers by performance-per-watt rather than pure processing power.
The list is a spin-off from the Top 500, which lists the world's most powerful supercomputers. This is the third Green500 list since its inception last year.
Big Blue has taken the top 15 places, as well as 44 of the top 48 places, in the Green500 list.
In first place is IBM's Boeblingen Lab supercomputer which is used for development of the company's blade computing systems.
"Energy efficiency has become just as important as simple raw performance for the modern supercomputer," said Dave Turek, vice president of Deep Computing at IBM.
"As applications for supercomputers increase, so does the attention on this aspect of their use.
"We have also driven advances that include our Cool Blue technology portfolio and added to our Project Big Green solutions that are designed to reduce data centre costs and energy use."
Roadrunner, the top-ranked supercomputer in the Top 500, is ranked third on the Green500 List, highlighting the increased focus on balancing power and efficiency.