2d tiling + sb -> no improvement in fill rate, curious

[curaga]

Things like using a 16-bit format would be cheating. It's standard to expect 32-bit RGBA.

If you mean something else than cheating like that, do you have any links?

[vadimg]

Things like using a 16-bit format would be cheating. It's standard to expect 32-bit RGBA.

If you mean something else than cheating like that, do you have any links?

I didn't mean any cheating, I mean GL allows to use different formats. Commonly used definitions of pixel fill rate typically do not include any specific requirements of formats, bpp, etc. Some definitions even say that it's just a theoretical value calculated from a number of ROP units, clocks, etc.

Anyway, it seems there are different versions of RV710 with different memory bandwidth, 6.4/8.0/10.4 GB/s for 4350, and 12.8 GB/s for 4550. With 32bpp formats (4 bytes per pixel), this gives a range from 1.6 to 3.2 Gpixels/s. If you have the chip with 6.4 GB/s bandwidth, this really could limit fill rate at 6.4/4 = 1.6. You probably just looked at the specs for other chip version, or at the max specs for the entire RV710 family.

[curaga]

Yes, mine is a ddr2 hd4350. I'm aware the 4550 can come with different memory, and only looked at 4350 specs.