Intel HD Graphics DirectX Developer's Guide (Sandy Bridge)

Intel® HD Graphics DirectX* Developer's Guide
The figure below shows a significant spike in GPU processing (aggregate duration of
time) over the sampling set. This indicated a large number of calls to Clear a buffer in
the histogram.
Figure 11 Intel® GPA Frame Analyzer Sampling Indicating a Hot Spot in the Clear Call
Recall in section “Tips on Texture Sampling / Pixel Operations” that unnecessary calls
to Clear have a performance impact on Intel processor graphics. Noting that we have
selected a low fidelity mode, the code was double checked and determined that while
Shadows were disabled in low fidelity mode, the sizeable texture buffer was still
getting allocated and Cleared. A simple condition to avoid this call when Shadows
were disabled yielded a slight performance boost to 15 frames-per-second as noted
below without changing the rendered scene.
58 Document Number: 321371-002US