Then we tried to analyze multicore memory access, in this case - from two threads executed on both processor cores.
As we found out, the reason was in a relatively narrow (64-bit bidirectional) L1-L2 bus of the CPU core, which effective bandwidth is lower than the theoretical bandwidth of the dual-channel DDR2-800. Nevertheless, our first analysis of AMD AM2 representatives ( Athlon 64 X2 and Athlon 64 FX operating at 2.0-2.8 GHz) showed that real memory bandwidth results that could be obtained on this platform were much lower than their theoretical maximum, and they were directly dependent on clock rates of a CPU core and a memory controller.
#FSB 1600 DDR2 800 DUAL CHANNEL DRIVERS FULL#
Theoretically, these platforms can reveal full bandwidth potential of the memory system, as they don't have the FSB bottleneck, shared by all CPU cores, which theoretical bandwidth is sure lower than the theoretical bandwidth of dual-channel DDR2. But this mark is still far from the theoretical bandwidth of DDR2-800 memory (12.8 GB/s), so we couldn't say that we revealed full performance potential of such memory.Īnalysis of multicore AMD platforms with the integrated DDR2 memory controller (starting from AM2) is of special interest. We almost reached real memory bandwidth results coming close to this mark.
In our previous analysis of this issue we reviewed Intel 975X and 965G chipsets with 266 MHz FSB, which bandwidth was about 8.53 GB/s. Its bandwidth is always lower than that of dual-channel DDR2 memory. In case of the Intel platforms, the key bottleneck is the FSB shared by all CPU cores (and system processors, if we speak about multiprocessor systems). Interest to such reviews is caused by the high performance potential of dual-channel DDR2 memory as such, which is still unrevealed due to bottlenecks, represented by other components of the memory system. We've already published many articles devoted to revealing performance potential of dual-channel DDR2-800 memory (and faster products). The First Test Results in RightMark Memory Analyzer
0 kommentar(er)
