The Eee Pad Transformer Prime by ASUS is the first tablet to run the Tegra 3 processor. Photo courtesy of NVidia

Nvidia has unveiled its long-anticipated Tegra 3 processor, the world’s first quad-core chip designed specifically for mobile devices.

The Tegra 3 is the world’s first quad-core ARM A9-based processor, and features a 12-core GeForce graphics unit. Nvidia says the Tegra 3 offers three times the performance of its previous dual-core Tegra generation, and boasts improved multitasking, better web browsing, and smoother app performance.

The new chip will make its first appearance in the Asus Eee Pad Transformer Prime — basically a higher-end version of Asus’ Eee Pad Transformer tablet, but with better cameras (8 megapixels for the back, 1.2 megapixels for the front), much more storage care of 32GB and 64GB versions, and, of course, the brawnier Tegra 3 chip.

Naturally, with such a boost in power, our thoughts turn to battery life. After all, what good is a beefier processor if you have to plug your tablet in for recharging every few hours?

Well, Nvidia and Asus promise the Tegra 3 won’t suck down power as quickly as you think. In fact, Asus says we’ll be able to watch up to 12 hours of HD video with the Prime running on the Tegra 3.

So how do they do it? It’s all about Variable Symmetric Multiprocessing, or vSMP for short. Essentially, tucked inside the Tegra 3 is a fifth “companion” processor that’s designed to kick in during times of low processing loads. The four main processors are only used when peak performance is required, such as when you’re playing games, multitasking or actively browsing through Internet pages. But when you’re simply reading a static web page, or when your tablet is otherwise sitting idle, the Tegra 3’s four primary processing cores shut off completely so your battery life won’t be sapped.

As we just shared in our coverage of leaked details concerning the HTC Edge, processor companies like Nvidia, Intel and AMD have long leveraged multi-core designs to mitigate diminishing gains in pure clock speed. So, for example, while it may be imprudent or technically infeasible to clock a mobile phone processor at, say, 2GHz for a variety of reasons, a company can roll out a multi-core chip at a much lower clock speed and still deliver faster performance (if not also improved power management, as vSMP shows us).

Mobile operating systems and apps should be coded for multiple cores to take maximum advantage of workload distribution, but once they are, they really begin to sing.

Previously referred to as code-name “Kal-El,” Rumors had pegged Amazon’s Kindle Fire to be the first to run on the Tegra 3. But, no, now we know this isn’t true.

By the end of the year, there should be about 40 games specifically tailored to leverage the Tegra 3’s processing power, with 15 available in Tegra Zone (Nvidia’s Android app that highlights Tegra-optimized applications).

Asus says the Prime is targeted at the premium end of the tablet market, with the 32GB version starting at $500, and an optional keyboard dock costing another $150. Although we haven’t yet been given a specific release date, expect to see the Transformer Prime in stores some time around the New Year.