On Friday, Google began pushing out the promised Jelly Bean update for the Motorola Xoom. While the Nexus 7 is the current watermark for what an Android tablet should be, the Xoom was the first tablet to ship with a version of Android designed for tablets. Many of the features in Ice Cream Sandwich and Jelly Bean originated there.

The Xoom is getting a bit long in the tooth and it has never been a big seller, but it’s still the only extant 10-inch Google Experience Device—the phones and tablets that Google chooses with each new Android revision to show off the stock look and feel of the operating system. Older hardware or not, the Xoom running Jelly Bean still represents Google’s standard for how a 10” Android tablet should be done. It will also tell us something about how Jelly Bean will run on older hardware, in the event that Google’s partners actually get on board and push out the update.

Jelly Bean on the Xoom: No surprises here

Jelly Bean on the Galaxy Nexus, Nexus S, and Nexus 7 have all used variations on Android’s phone layout: the Android software buttons across the bottom of the screen, the Google Now bar across the top of the screen, and a persistant dock that stores a few icons and the application drawer. Notifications are accessed by swiping down from the top of the screen, where the network and battery indicators and clock live. When invoked, the application switcher takes over the entire screen.

Rather than switching to a Nexus 7-style smartphone layout, the Xoom’s Jelly Bean upgrade continues to use the tablet-style layout first introduced in Honeycomb (which itself was originally introduced on this very tablet): software buttons in the lower-left corner, notifications in the lower-right corner, application drawer in the upper-right corner, and Google Now button in the upper-left corner. The application switcher shows up on the left edge of the screen.

Tablet or smartphone, the rest of Jelly Bean’s user interface improvements make the move over to the Xoom without issue—the clean whites and blues of Jelly Bean are far and away more refined and attractive-looking than Honeycomb’s luminescent theming, which always seemed to be trying a bit too hard.

Also present: the improved, predictive keyboard; home screen icons and widgets that move automatically to make room for new ones; the Google Now and voice dictation features; the refined Roboto font; and the improved notifications. This is a pleasant change from the state of things on the iOS side of the fence, where even if your device can run the latest operating system it may not get all of the latest features. Voice dictation and Google Now in particular work well on the Xoom. In a fairly quiet room with the tablet held about a foot and a half from my face, the tablet correctly understood every word I said, even “Ars Technica," a phrase that routinely trips up speech-to-text software.

Project Butter: Held back by the hardware

One of Jelly Bean’s other banner features, increased performance, also comes to the Xoom. That is, as long as you properly manage your expectations.

Let’s compare: the Xoom uses NVIDIA’s Tegra 2 T20 SoC. The CPU part of the chip is comprised of two ARM Cortex A9 cores running at 1.0GHz, while the GPU runs at 333MHz and uses four pixel shaders and four vertex shaders (adding up to “eight cores” in NVIDIA parlance). The Nexus 7 uses NVIDIA’s Tegra 3 T30L SoC. The CPU uses four ARM Cortex A9 cores running at 1.3GHz, while the GPU runs at 416MHz and uses eight pixel shaders and four vertex shaders (“twelve cores”). Both tablets use the same 1280x800 resolution for their screens. All of this is a very roundabout, technical way of saying that the Xoom has to push the same number of pixels using a good deal less processing power.

That said, Project Butter does have a noticeable impact on the Xoom. Animations that were occasionally capable of smoothness in Ice Cream Sandwich are now consistently smooth in Jelly Bean—things like flicking from home screen to home screen, opening and navigating the application drawer, and scrolling are consistently less jerky than before. Swiping between home screens using a live wallpaper (something that almost always caused lagginess in Ice Cream Sandwich) is nice and smooth in Jelly Bean. Using an app like CPU Usage Monitor confirms that the CPU clock speed ramps all the way up to 1.0GHz when the screen is touched, one of the lag-reducing optimizations made in Jelly Bean.

There are other places where things remain a bit jerky, owing mostly to the Xoom’s aging hardware. Things like swiping away notifications and open applications are consistently choppy, as are the animations that accompany opening applications from the home screen. This happens every time the actions are performed, indicating that the Xoom’s hardware rather than Jelly Bean is at fault. While these problems are exacerbated a bit by the Xoom’s screen, which is more than a little prone to motion blur, they go to show that Project Butter can only do so much for yesterday’s hardware.

Benchmarks and browsing: Quantitative performance increases

While the emphasis in Jelly Bean is on apparent speed—making Android devices feel faster by reducing lag and increasing the smoothness of transitions and animations—it also gives the Xoom some small but measurable increases in actual speed over Ice Cream Sandwich. These manifest mostly in our graphics and browser benchmarks.

The numbers from Geekbench and Linpack, the two CPU-focused benchmarks we usually run on tablets and smartphones, were more or less identical in both Ice Cream Sandwich and Jelly Bean. The numbers from GLBenchmark 2.1.5 tell a slightly different story however.

The scores for GLBenchmark’s Egypt and Pro tests don’t budge much—about 12 and 19 percent, respectively—but the performance increase is measurable and consistent. Whether this increase comes from improvements to Jelly Bean or improvements to the Tegra 2 drivers is difficult to say without more devices to test. Widespread performance improvements would suggest the former while improvements only in Tegra 2 devices would suggest the latter. For now, the upshot is that you ought to expect marginally better framerates on the Xoom in Jelly Bean compared to Ice Cream Sandwich.

The second major improvement is in the built-in browser’s performance. While Chrome is the shipping browser on the Nexus 7, devices like the Xoom and Galaxy Nexus are shipped with the stock Android browser and keep it as the default in Jelly Bean. There aren’t many changes to how it looks and acts, but the new version of Browser does bring much-improved SunSpider scores to the table.

What’s really odd here is that Chrome running in Jelly Bean took a bit longer to complete the test than did the same version of Chrome in Ice Cream Sandwich. Browser, on the other hand, improves its score by a healthy 27 percent, and takes roughly as long to complete the test as the faster Nexus 7 running Chrome.

Despite these improved numbers, Browser in Jelly Bean is still inferior to Chrome in actual usage. When scrolling down the Ars homepage, Browser loaded it more slowly and in large, noticeable chunks. If I scrolled quickly back to the top of the page, I had to wait for Browser to redraw everything even though the page had already been loaded just a few seconds before—neither of these things are problems in Chrome. Browser is still under active development in Android as of Jelly Bean, but benchmarks aside, I hope that Chrome becomes the platform’s default browser sooner rather than later.

Conclusions: The right software in search of the right hardware

The best word to describe Jelly Bean on the Xoom is “consistent.” The look and feel of the operating system is consistent with its look and feel on the Nexus 7 and the Galaxy Nexus, giving us a glimpse of a world where Google had iOS-like control over all aspects of the software experience. The tablet’s performance is more consistent, and while the hardware’s age means there are still some areas where animations remain a bit choppy, even that choppiness is now reliable and repeatable, rather than hit-or-miss as it was before. Again, in a word: consistent.

The biggest fly in the ointment is that the app ecosystem for Android tablets is still pretty bleak. While an app designed for a phone might look passable on the Nexus 7, it continues to look ridiculous on the Xoom’s 10-inch screen.

Even if the Nexus 7 is enough of a success that developers begin targeting it and optimizing their apps for its screen, it still won’t do much for the likes of the Xoom. Apps designed for a 7-inch screen will probably look better on a 10-inch screen, but they still won’t make as good a use of the space available as do iPad apps.

While Ice Cream Sandwich and Jelly Bean have made the Xoom a much more capable, complete product than it was when we originally reviewed it, this is still hardware that was developed and released when the first iPad was the primary competition (it shows in the Xoom’s thickness and weight). The Xoom's screen—which has poor contrast ratio, is prone to motion blur, and has (by today's standards) pretty low pixel density—is also a bit of a problem. Jelly Bean should convince even longtime iOS holdouts that Android on a 10-inch tablet can be competitive and even pleasant. Now we just need it to show up on modern hardware.