There are different ways to look at this - a card could pull 100s of watts and it is going to push out a lot of heat but if it has effective cooling and somewhere for that heat to go the card itself could well run cool. On the other hand a card with a much lower power consumption but sub-par cooling might run much higher temperatures as measured by software.
God I hated some of the FX series cards
The FX series was largely pretty hateful - in terms of performance only the late 59xx models were really anything worth talking about and that usually only came from overclocking them and while by the time it was exposed by newer software fairly late in the day they were lacking in colour precision in some functions and processing some features of new APIs at reduced resolution to make up for hardware inadequacy.
If I hadn't got my hands on one of those special edition Gainward 5900XT that used higher spec detuned VRAM that could be overclocked by 50% and got a 50% core overclock with a replacement heatsink those would have been very dark days.
Repurposed an old Intel heatsink but amazingly it both fitted perfectly and also worked - allowing me a much higher overclock than the stock cooling:
EDIT: LOL forgot I did this - got my hands on a 5950 Ultra BIOS and customised it to work on the 5900XT to get better memory timings and a few other performance tweaks and I thought I was so cool: