I have 4 1gb sticks of Corsair Dominator 1066MHz PC2-8500 RAM. Identical timings and voltages, but one set is version 4.1 and one set is 6.1 and they WON'T WORK TOGETHER. All of the RAM works individually and all of the RAM slots work (new motherboard Gigabyte EP45-UD3R).
You can certainly argue that their RAM should be compatible, particularly when the specs are identical. It isn't like you were trying to get their RAM working with anothet vendor's RAM. Have you checked that SPD values are the same?
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