[Intel-gfx] FPS performance increase when deliberately spinning the CPU with an unrelated task
pcjc2 at cam.ac.uk
Tue Oct 26 12:34:34 PDT 2010
On Mon, 2010-10-25 at 13:14 -0700, Eric Anholt wrote:
I'm taking a bet on memory bandwidth being the constraint for fill
limited applications. glxgears manages 59fps at full screen (minus title
bar), which is 1680x1024, giving a pixel rate of approx 100Mpix/second
Assuming 2 bytes per pixel (ignoring possibility of depth / stencil
writes), that is 200M bytes / second.
Now I don't know what the likely memory bandwidth of the GMCH is, but I
bet with scan out and other activity going on, we'll be pushing it quite
hard to sustain that framerate.
I'm targeting a desired ~15-20fps at nearly full-screen for my circuit
board design app, so I will need to be careful with my code!
This said, some top-range current cards from other manufacturers are
claiming fill-rates in 10s of BILLIONS per second, and memory bandwidth
of 10s up to ~100 GB/sec! (Although it comes with more than half the ram
I have in this laptop, and probably costs about 1/2 - 3/4 what the
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