CPU Guide

Memory Channel Scaling with Sandy Bridge-E - A Core i7-3960X Experience

Memory Channel Scaling with Sandy Bridge-E - A Core i7-3960X Experience



Results - SYSmark 2007 Preview & Lightwave 3D 9.0

Results - SYSmark 2007 Preview

We expected memory intensive tests like the 3D modelling and video creation test suites of the SYSmark 2007 to show obvious results as we scale down the number of memory channels; however, the results were not so clear cut. The quad-channel mode came out tops in the Video Creation test with a score of 392 while its 3D modelling score was lower than that of the triple and dual-mode configurations. Its overall rating was about 1.5% higher than the second highest score of the triple-channel mode configuration, which itself wasn't much faster than in dual-channel mode.

While the installed amount of memory differs from dual, triple and quad-channel memory configurations, we know from internal testing that for our tests, the amount of memory doesn't really assist in lifting performance scores. As such, SYSmark 2007 score breakdown shows that video creation seems to benefit from more memory bandwidth (up to 7% improvement), while all other test suites roughly reported little change.

 

 

Results - Lightwave 3D 9.0

With the results from Lightwave 3D 9.0 (64-bit), we also seem to have run into a brickwall with memory channel scaling.  The time taken for the rendering tasks failed to point to anything conclusive. This is probably in-line with our own expectations as this rendering benchmark scales with CPU power than any other system factors.


 

3D Modelling Faces CPU Bottleneck

From the results gathered from the above benchmarks, it seems that by varying the memory bandwidth from 51.2GB/s to 21.2GB/s, it does not have much impact on 3D modelling tests. As such, it faces a CPU bottleneck rather than memory bandwidth limitations.