There is something wrong with the source of this information.
If you never have lag on the ps3 and wii60 download fine, then you have either a problem with exaggeration, or you are talking about "installing" the update, not downloading it.
If your ps3 never lags, then downloading is impossible to be a problem. Lag involves downloading and uploading bits from the net. An update downloads directly to your hard-drive, so, in effect, it is the exact same thing as playing online.
You must be complaining about installing the update, which I agree, tends to take several minutes, usually 3-10 on average.