how many cpus and how many cores are totally two different things~
Titan:18,688
AMD Opteron 6274 16-core CPUs, this is already 299008 cores~
Dude, It actually does not matter how many CPU were there in a super computer, what matter most is core and threads, which 1 core process 1 task at the CPU refresh rate, and 1 thread carry each single task into the processor.
If you have less CPU and more core but with less computed task done, that means the "interfacing" (Shoving task into core) is not quick enough or the bus does not support the same parallel process to the processor.
When you compare Tianhe-2 to DOE Titan. Tainhe-2 Have 32,000 Intel E5-2692 12 Core Processor. And 48,000 Intel Xeon Phi 31S1P 57 Core Processor, which give Tianhe-2 a Total of 3,120,000 core pure processor power. Which mean at given rate clock, Tianhe can process 3,120,000 process at the same time. And the peak performance is 52.7PFlop
While Titan run on 18,688 AMD Opteron 6274 16 Core CPU, and 18688 Nvidia Tesla K20x 12 Core GP, which give the titan just 560,640 Core pure processor power. Which mean at given clock rate, the computer can refresh 560,640 task at the same time, (Which is about 1/6 of Tianhe-2 Processing power) but it give a whopping 27PFlop speed.
The implication is huge, While more processor and more processor core means more Voltage to be consume, the space and maintenance effect is shorten and which mean the supercomputer is a lot easier to service and did not drain a lot of power.
Another advantage on this is that while the Chinese supercomputer uses pure muscle (Processing power) by denoting a large number of core to processing. Which mean the expansion of the system would determine how the software interconnecting those hardware, which limit the number of hardware it can interconnect. But with Titan, the software control multiplied the system speed and with less physical hardware connected to the supercomputer (1/6 of the size of Tianhe-2 hardware) the upgrade of titan is not so much bounded by the physical limit. And given if Titan uses the same physical processing power to the Tianhe-2 counterpart, the system will be 2 times as fast as Tianhe-2 while Tianhe-2 would need 4 times as much as physical hardware to get to that level.