It took a long time, but Apple announced a few days ago, through a new support document, which recognized distorted video problems on Macs Pro equipped with the ATI X1900 XT graphics card. Owners of these machines now have a special extended warranty.
According to the company, Macs Pro equipped with such a chipset were sold between August 2006 and January 2008. To find out if your affected, make sure that the last four digits of your graphics card serial number contain the V6Z code.
Affected users can take their graphics cards to authorized centers or official Apple stores to verify eligibility and exchange the unit for a new one (not specified). Of course, if you are one of the lucky ones and have never experienced strange behaviors with your machine, there is no need to exchange.