Unlike the last generation, the PS4 and Xbox One are both based on very similar PC architecture, shrinking the gap that existed between the PS3 and the Xbox 360. Each use similar eight-core, x86 processors designed by AMD, which means is that games developers will find it easier to port (that is, to modify) their games for PS4 and Xbox. In theory, games will look and run similarly on each console.
After years of pushing the most they could out of 512MB of RAM, the new consoles are finally getting a substantial upgrade. An impressive 8GB of memory is being crammed into each console which, compared to the seventh gen, will feel like a lightning strike to your console. With the new processors as well, expect these consoles to run much, much faster. But like a computer, more RAM means the Xbox and PS4 will be able to perform multiple tasks at once, so, for example, you can download an update in the background while playing a game, without any evidence of slowdown. Microsoft has integrated this feature into the Xbox One nicely, allowing instant switching between games and media functions.
But the way the RAM is allocated and the type of RAM used can make a difference. Sony is using the latest GDDR5 RAM, while Microsoft is sticking with older DDR3 RAM. GDDR5, in general terms, outperforms DDR3, and while DDR3 has some benefits, consumers will notice better general performance with systems that use GDDR5.
Raw figures don't tell the whole story, though. We won't know whether one console will outperform the other until we can get our hands on some games and do a side-by-side comparison.
For more information on these components, see our desktop computer buying guide.