As non-volatile storage devices begin to exceed 1 GB in capacity (where the ambiguity begins to routinely impact the second significant digit), GB and TB almost always mean 109 and 1012 bytes.
æz nˈɑːnvˈɑːlɐɾəl stˈoːɹɪdʒ dɪvˈaɪsᵻz bɪɡˈɪn tʊ ɛksˈiːd wˈʌn dʒˌiːbˈiː ɪn kəpˈæsᵻɾi wˌɛɹ ðɪ ˌæmbɪɡjˈuːɪɾi bɪɡˈɪnz tə ɹuːtˈiːnli ˈɪmpækt ðə sˈɛkənd sɪɡnˈɪfɪkənt dˈɪdʒɪt, dʒˌiːbˈiː ænd tˌiːbˈiː ˈɔːlmoʊst ˈɔːlweɪz mˈiːn wˈʌnhˈʌndɹɪd nˈaɪn ænd wˈʌn θˈaʊzənd twˈɛlv bˈaɪts.