I put my graphics card in the oven

cracked solder joints?

eutectic tin/lead solder melts at 183ºC so the 190ºC you used is lill higher, remelts the joints and bonds are reformed. Though I have to say, 10min heat (+cooldown at room temp) is a little long time for a reflow cycle. Might have been better to crank it up to 220ºC for shorter period. lol

pretty neat anyways

edit, the hardforum thread shows pics of the board with RoHS compliant sticker, 'normal' leadfree solder melts at 218ºC so it should't have melted the joints only at 196ºC (385f). Maybe the solder used is some more uncommon type or the temperature control of the oven is a bit off...

Most likely the oven temperature was off. Domestic appliances are not particularly accurate at setting or maintaining a temperature.

@ thaoval: As I gather, it is more like metal fatigue: as the card heats and cools it expands and contracts but not evenly, causing localised stress on certain joints which ulitmately fail and become non-conductive.
Sustained high temperatures or constaint use do not cause this because there is no heating/cooling cycle.

the stress points cause dry joints to form i mean..

and different materials used in a modern card have different coefficients of thermal expansion, the board itself, solders used, the component casings and substrates and the silicon chips themselves. all these contribute to stresses that affect the solder joints and eventually breaks them...