I am in a quandry, I am probably going to update my DA 533 with either of the above mentioned cards. They are the same price at OWC ($299). The two big differences that I see are that the 1.4 has the 2MB L3 cache and the 1.7 uses lower voltage so it might be quieter. I don't really use my computer for much besides the usual email/internet/itunes/iphoto with imovie/idvd every now and then. Any opinions from those who have upgraded or are also thinking of doing so? Thanks.