Approaches for 2D tile rendering

That’s faster than the 5850, which seems ridiculous given the card almost cost as much as the laptop.

That can mean a lot of things and it most probably happens because of difference in the hardware architecture (and driver). Maybe the Intel card uses system memory as video memory which can be faster to copy to than GPU memory or maybe simply TexSubImage is not well optimized in ATI drivers (I would bet for the first one).

Or even because the texture data format is better suited intel.
Did you try different formats such as GL_BGRA8 etc ?

No, everything was RGBA. I doubt I’ll bother unless I hit a performance problem. Thanks for the thought I’d forgotten about that.