Looking at individual components of the PlayStation 4, Sony's brand-new hardware is anything from 6x to 16x more powerful than its predecessor - but there's one area that has remained completely unchanged. The PS4's 500GB 5400rpm hard drive isn't just of a similar spec to the PS3 Super Slim's - on our launch model at least, it's actually the exact same unit. Thankfully, this is the one part of the hardware that users are free to upgrade themselves - so that's exactly what we did.Our objectives here are twofold. On the one hand, with game installs often ranging from 20-50GB, it's clear that the PS4's stock hard drive can fill up pretty quickly - so we're interested in getting the most cost-efficient upgrade. But more than that, we wanted to see what happens when the standard hard drive is replaced with better, faster technology. Would we see faster boot times? A more responsive front-end? Would games load quicker? Would intrusive streaming issues and pop-in be resolved?It's a topic we've been thinking about for some time, but only now do we really have a wide enough range of software to test in order to come up with some tangible results worthy of a buyer's guide. For example, as we mentioned in our Face-Off, Square-Enix's Thief suffers from some poor frame-pacing issues which appear to be related to streaming new assets from the hard drive. Meanwhile, the recent release of RedLynx's Trials Fusion allows us to put virtual texturing technology - also seen in id software's Rage - to the test. On PS3, swapping to a better drive could massively improve the cohesiveness of the game's presentation. Could we see similar improvements on PS4, with the added bonus of more space to store our games and media?