Now playing: Watch this: New Xbox may bring 4K, Oculus support

The Electronic Entertainment Expo (E3) will introduce the world to a host of exciting new video games this week. But what about video game hardware? We've heard that the Nintendo NX and Sony's PlayStation Neo won't make it to this year's expo.

Microsoft, however, might be the exception to the no-new-console rule. The Xbox and Windows giant has not one, not two, but four rumored Xbox devices that could appear at E3 2016.

Here's what the rumor mill tells us about each one.

Update:The Xbox One S and Xbox Scorpio are real.

Xbox One Slim

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The current Xbox One is huge. It makes the rival PS4 look tiny by comparison. But imagine if Microsoft shrunk it down to become the smallest Xbox ever.

According to sources who spoke to Kotaku, Polygon and The Verge, that's exactly what's happening: the Xbox One Slim (not a real name) will be 40 percent smaller than the current model. It will allegedly be cheaper, too, and yet offer 2TB of storage space -- double the capacity of the highest-end Xbox One available now.

Rumor says it'll come with a slightly redesigned Xbox One gamepad, and may natively support 4K televisions as well. We don't have any leaked pictures of the new Xbox yet, but sources believe it's slated to ship in August.

Update: Behold, the first leaked picture of what appears to be the new Xbox One S.

While it's normal for Microsoft, Sony and Nintendo to release slimmer versions of their consoles during their long lifespans, such as the PS3 Super Slim and Xbox 360 Slim, the next rumor you're about to read is for something much different.

Xbox One VR

If you wait until late 2017, say some of the same anonymous sources, there could be a much more powerful Xbox One on tap -- one that supports virtual reality. The Xbox One VR (also not a real name), codenamed "Scorpio," is allegedly a beefed-up Xbox One with a new graphics chip that gives the console four times the horsepower. That's enough graphical oomph, reportedly, to power an Oculus Rift VR headset.

Microsoft doesn't have a VR headset of its own, and it denies interest in making one anytime soon. (The Microsoft HoloLens is not a VR headset, and is likely years away). So it's initially surprising to hear that Microsoft might have an Xbox designed to support virtual reality.

But anonymous sources aren't the only ones who are suggesting that Microsoft might have suddenly taken an advanced interest in VR. A game developer at a "well-known European studio" let slip to Ars Technica that his company was working on an Xbox One VR title for 2017, and the official E3 exhibitor list now has a category for Xbox One Virtual Reality developers.

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Besides, Microsoft already had a partnership with Oculus: it provides Xbox One gamepads for every Oculus Rift sold, and is developing a VR version of its mega-popular video game Minecraft for the Oculus platform.

An Xbox One VR sounds like a possible foil for the PlayStation Neo, assuming it exists. It, too, is allegedly a beefed-up console with a new graphics chip expressly designed to support virtual reality -- only in Sony's case, it would be powering Sony's own PlayStation VR headgear.

And according to Polygon's sources, that new VR-capable Xbox could be even more powerful than the VR-capable new PlayStation. While leaked documents obtained by our colleagues at Giant Bomb suggest the PlayStation Neo will boast raw performance of roughly 4.14 teraflops, Microsoft's "Scorpio" is allegedly targeting 6 teraflops.

Since today's PlayStation 4 is slightly more powerful than today's Xbox One, it could mean a role reversal for the two consoles.

Xbox One Mini and Stick

If you believe the sources of veteran Microsoft reporter Tom Warren, Microsoft has been working on a pair of Xbox One media streaming devices for years: one a small set-top box to compete with the Apple TV, and the other a HDMI stick more like a Google Chromecast.

And if you believe Brad Sams, another Microsoft reporter who correctly predicted the Xbox One Elite Controller, Microsoft will actually announce both those streaming devices at E3 this year for roughly $150 (approximately £104 or AU$208) and $100 (approximately £69, AU$138) respectively.

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The Xbox One Mini (not a real name) is believed to be a tiny stripped down Xbox that would be able to play lightweight games and apps, taking advantage of the fact that Microsoft is unifying its Windows and Xbox app stores to make some Windows programs available on Xbox and vice versa. Though no rumor has yet corroborated this, it would presumably ditch the Xbox's optical drive.

Meanwhile, the Xbox Stick (yet another made-up name) is allegedly pegged as a way to stream games from an Xbox in one room of your house to a TV in another room using wireless technology. That wouldn't be too much of a stretch, given you can already stream Xbox One games to a Windows 10 PC.

Overarching Xbox vision

Why four devices? We don't know for sure -- but they appear to revolve around a new Microsoft initiative, codename Project Helix, to bring the worlds of Windows and Xbox much closer together.

This March, we learned that Microsoft intends to release every new game it creates for Windows and Xbox simultaneously. One month later, Microsoft announced that it would fulfill its long-standing promise to let the Xbox One run Windows apps -- not just games.

Both announcements rely on developers building so-called "universal" apps on a set of tools and practices dubbed the "Universal Windows Architecture" (UWA).

But Microsoft needs new hardware to get developers excited enough to build those apps in the first place. If Microsoft can tell developers that their UWA apps will run on a host of new devices that consumers are likely to have in their homes, including ones as cheap and portable as HDMI sticks, that could be some serious incentive to build for Microsoft's platform -- where Microsoft gets a cut of every sale.

If it works, it could be pretty nice for gamers too: In March, Xbox boss Phil Spencer imagined a future where your game library would never go out of date. Traditionally, each new generation of game consoles isn't "backwards-compatible" with games from previous generations. They typically don't work due to differences in the architecture of the processors inside.

But if Microsoft can get developers to build universal apps that work across different types of hardware, console gamers could enjoy the same benefit as today's PC gamers -- whose games just keep looking better, instead of going obsolete, as they upgrade to more powerful processors and graphics cards.

Scroll down for a reverse-chronological look at the latest rumors.

May 31, 2016

Microsoft cuts the Xbox One's price to $299 through June 13 -- June 13 just so happens to be the day when Microsoft will hold its E3 press conference.

May 27, 2016

A game developer at a "well-known European studio" tells Ars Technica that his company is planning a new VR game for 2017 which will allegedly work with the Xbox One -- a console which isn't currently compatible with any VR headsets.

NeoGAF forum user 00ich discovers that the Entertainment Software Association, which sponsors E3, has specifically created a category for companies building VR software for the Xbox One.

Tony Bartel, COO of video game retailer GameStop, corroborates the rumors by saying he expects new game consoles to be announced at E3 this year.

May 25, 2016

Sources tell Kotaku that Microsoft will release "at least two" new Xbox game consoles over the next two years: a cheaper, smaller version of the current Xbox One with a new 2TB hard drive this year, to be announced at E3, and a more powerful Xbox One next year with a faster GPU capable of supporting the Oculus Rift VR headset.

Polygon corroborates the Kotaku report with its own anonymous sources, and adds that next year's more powerful Xbox One will be four times as powerful as the current console, with a performance target of 6 teraflops, and is designed to be backwards compatible with all current Xbox One software.

According to Polygon sources, the other cheaper, smaller Xbox One variant will be the smallest Xbox ever made and is scheduled to ship this August with a redesigned controller.

Sources tell The Verge that the smaller, cheaper Xbox One mentioned by Kotaku will be 40 percent smaller than the current Xbox One and likely support 4K video playback.

During a video podcast, tech journalist Brad Sams claims that Microsoft is "going to be announcing at least two streaming devices at E3." He describes one of them as a streaming media stick the size of a Google Chromecast for around $100, and the other as a $150 to $175 Apple TV competitor which could play lightweight games.

He also says that Microsoft is experimenting with bringing the Xbox interface to Windows PCs as a replacement for the old Windows Media Center, and that Microsoft may be planning another Xbox for next year with 4K video playback.

The Verge adds that Microsoft has "long been experimenting with a Chromecast-like device that would allow you to stream Xbox One games from a main console in a living room to a second TV elsewhere in a house."

April 27, 2016

Tech journalist Brad Sams cites "sources within the company" that Microsoft will have a large hardware announcement at E3, and separately that the Xbox One will ship with a new controller with a different color than the current black gamepad.

April 19, 2016

The Verge's Tom Warren reports that Microsoft has been testing "a variety of prototype Xbox devices" using beefed-up PC components to make them faster.

April 12, 2016

In the Federal Communication Commission's public database, NeoGAF forum member ekim discovers that Microsoft is attempting to certify new Wi-Fi radio modules, likely for a new revision of the Xbox One.

March 30, 2016

Microsoft confirms that it will unify the Windows 10 and Xbox One app stores, allowing Xbox game consoles to act even more like Windows computers by running the same applications.

March 4, 2016

Xbox boss Phil Spencer clarifies that future Xbox consoles won't become upgradable PCs which require a screwdriver to replace their components. Instead, he meant that it won't necessarily take the seven to eight years of a typical console cycle before the Xbox becomes more powerful.

March 1, 2016

At a media event attended by CNET, Xbox boss Phil Spencer hints that Microsoft might not wait for a new generation of game consoles to introduce new hardware, and that the hardware might be upgradable.

Xbox boss Phil Spencer explains why Microsoft believes it doesn't need to build a VR headset to go with its Xbox One game console.

Microsoft developers reveal to CNET that the company's future in-house games will arrive on Xbox and Windows on the very same day.