It could be a hoax but it looks very legit, if this is a fake someone definitely wasted a lot of time. The source is unknown but it could be someone from a firm that makes coolers for NVIDIA graphics cards. The renderings show the card has 16 memory chips, eight on the front and eight on the back, good for up to 1GB of GDDR3 memory. The unusual memory configuration may be evidence to support the rumour that the GT200 will have a 512-bit memory bus.
NVIDIA's GT200 GPU is expected to be released in July but the exact launch date isn't known yet.