GPU die temps hover around 42 celsius at stock speed, idle (with two 80 mm case fans blowing air over the heatspreaders).
The hottest i've seen it get at stock speed was 44 celsius.
GPU at 420 mhz, memory at 350 mhz, while running 3dmark03, hottest i saw it get was 47 celsius and the gpu temp hovered at 43 celsius while at idle.
GPU at 450 mhz, memory at 355 mhz, while running 3dmark03, i saw it top 48 celsius and it hovered at 44 at idle.
I'm not planning on pushing it past 450 mhz.