A flood of articles similar to IEEE Spectrum article “Is Multicore Bad News For Supercomputers?” are hitting the web.
“The worldwide attempt to increase the speed of supercomputers merely by increasing the number of processor cores on individual chips unexpectedly worsens performance for many complex applications, Sandia simulations have found.
A Sandia team simulated key algorithms for deriving knowledge from large data sets. The simulations show a significant increase in speed going from two to four multicores, but an insignificant increase from four to eight multicores. Exceeding eight multicores causes a decrease in speed. Sixteen multicores perform barely as well as two, and after that, a steep decline is registered as more cores are added.
The problem is the lack of memory bandwidth as well as contention between processors over the memory bus available to each processor. (The memory bus is the set of wires used to carry memory addresses and data to and from the system RAM.)”
Related Stories
Multicore CPU gains stop at eight : More core ≠ Moore’s Law
Sandia simulation shows that many-cores reduce compute power
More Chip Cores Can Mean Slower Supercomputing, Simulation Shows
Scientists Find Too Many Cooks - er, Cores - Spoils the CPU
