NVIDIA 7600 card, core2 duo at 2.5 Ghz -- even with graphics at full fidelity and highest settings, there is no graphic for the circle of flame on the TB. You can see the cast animation, but no circle of flame shows up on the ground to see where the spell is located. Its quite annoying because its hard to avoid if you can't see it.
On my laptop, the circle works fine, even on lowest graphics settings.