So, in other words, i subtracted time that both actually have to spend, for no good reason.
In order to further make results look better, I only subtracted it from my database, instead of running tests myself and subtracting it from both.
Look, disk time counts, whether it's hadoop loading it into the memory of a given machine, or you reading it from disk and transferring it into a GPU piece by piece.
Your "hopefully it will be irrelevant" is, well, crazy. I work for an employer with plenty of in-memory systems (very large ones in fact), and it certainly doesn't discount disk time. In fact, it matters a lot!