That being the case, here's what we know is inside PS4 development kits—model # DVKT-KS000K—as of January 2013. As you'll see, some things have changed since earlier kits became available in March 2012.
System Memory: 8GB
Video Memory: 2.2 GB
CPU: 4x Dual-Core AMD64 "Bulldozer" (so, 8x cores)
GPU: AMD R10xx
Ports: 4x USB 3.0, 2x Ethernet
Drive: Blu-Ray
HDD: 160GB
Audio Output: HDMI & Optical, 2.0, 5.1 & 7.1 channels
If you think the HDD is small, remember, these are the specs for a machine that developers are using to make games on, not the console you'll own and be storing media on. And don't worry about having two ethernet ports; as this is a dev kit, one is there for local sharing/testing purposes.
Interestingly, while some of these specs (such as the 8x core CPU) match with those reported by Digital Foundry only a few days ago, others like the RAM (DF reported 4GB of GDDR5, while we've heard 8GB) differ.
We've learned there's a headphone jack on the front of the console, but it's unclear whether that's just for dev kits or is an intended feature of the final retail console.
CONTROLLER
Ever since the release of the original PlayStation, Sony has maintained roughly the same basic controller design. This trend may be continuing with the PS4, because we've learned that developers are working with—and dev kits support—both the Sixaxis and DualShock 3 controller. This suggests that, for the most part, the design and capabilities of the PS4's controller will be similar to those on the PS3. The documentation also shows a Move controller, suggesting Sony's Wii-style motion wand will work with the new console.
There is a new controller in development for the PS4, though, known internally as the Orbis Development Tool, and while it keeps many of the same features as the current pads—like the four iconic PlayStation face buttons, two thumbsticks and shoulder triggers—there's one key addition.
THE CURRENT PS4 DEV KIT, AT A GLANCE
8GB system memory, 2.2GB video memory
4x Dual-Core AMD64 "Bulldozer" CPU, AMD R10xx Liverpool GPU
New controller features touch pad
Can link PSN accounts to controllers, allowing for multiple logins.
British site CVG speculated last week that, because they'd heard the PS4's controller was "trying to emulate the same user interface philosophies as the PS Vita", that meant it would feature a touch screen. Instead, the Orbis' controller features a capacitive touch pad, like you find on the back of a Vita (presumably it's also on the back of the PS4's controller), that can recognise two-point multi-touch. The entire pad can also be "clicked" for an additional input button.
The PS4's controller will again be capable of motion-sensing, like its PS3 predecessors, only now with improved technology like tilt correction. It will also feature vibration, which Sony has thankfully learned is a next-gen feature you need to launch with. It'll also have an RGB LED light in it.
While there have been reports of the PS4 controller featuring "biometric" technology, there was no mention of it in the information we were provided.
There's one other addition to the PS4's pad you won't find on a DualShock 3: a "Share" button. We're not exactly sure what it does. The most likely use would be to allow users to share some aspect of their gaming experience to Twitter or Facebook. Maybe a screenshot? We have no idea. But that Share button might have something to do with...
ACCOUNTS
Sony is trying to change the way you think about user accounts with the PS4. As it stands now, and this applies to all current consoles the PS3 (and the Wii U), when you log in, you log in as a single user. With Orbis, Sony is moving the place of "ownership" away from the console, with something it calls "multi-user simultaneous logins."
Which means that the PS4 will let more than one person be logged into the same system at the same time. It achieves this by linking control pads to user accounts; as each new controller syncs with the system, that player's account can be logged in as well. Accounts won't be "locked" to a controller; you'll simply be prompted to sign in to an account every time an extra pad is connected to the console.
One application we learned about for this feature would be that, were four players in a co-op battle able to defeat a boss, then all four would receive trophies.
We only learned of this feature in relation to local accounts stored on the console itself. It's unclear whether you'd also be able to do this via the PlayStation Network if you were playing online.
when are you due?