Without warning, Apple has released a public beta of Safari 4 for both Mac OS X and Windows. The update brings a variety of new features, broader support for emerging Web standards, and a much more native UI for Windows users, so we took it for a spin.

Top Sites

Headlining Apple's feature list is Top Sites, a display of thumbnails of your most frequently visited sites—perhaps more well known as the "Most Recent" home screen in Google's Chrome browser and Opera's Speed Dial (Microsoft also has a version in betas of IE8). Apple has attempted to innovate here though, by applying a pointless 3D effect to the view.

Top Sites defaults to showing 12 sites, but you can switch between larger screen shots (six only) and smaller thumbnails (20). In addition, you can permanently remove any site from being displayed or make a site sticky regardless of its status on your frequently visited list. Clicking any site will zoom and fade the viewport (the area where the page is rendered) into the browser's last-saved thumbnail, replacing it when the site has finished loading.

The whole experience is flashy and graphically impressive, but frivolous and unnecessary. Finally, we couldn't help but notice that Top Sites is designed around the mouse. Where other browsers allow for picking a site with a keyboard shortcut (typically a number), for example, you are required to use a mouse to select a Top Site.

Cover Flow, Apple's flashy UI that now permeates everything from music browsing to file management, has also made its way to Safari. The Bookmarks and History management area is now centered around a Cover Flow panel. Thumbnail previews are generated for both the pages in your browsing history and bookmarks, and while Cover Flow is indeed handy for picking out a diamond in the rough, the thumbnail process seems to be a little buggy. In addition to taking a bit longer than we expected to create previews for the pages in our history, some basic pages—such as Apple's own Safari welcome page, never got the treatment. Good thing there's a "beta" tag.

For those who still are not into Cover Flow, it can be hidden. While there is no menu option to accomplish this, you can simply drag the handle at the bottom of the Cover Flow view all the way up. Only the History and Bookmarks search box remains in a black bar at the top of the window.

Apple has also redesigned Safari's UI on Mac OS X and especially on Windows, and the company clearly took a tab page (or three) from Google Chrome's book. "Tabs on Top" means exactly what it says: instead of your tabs pointing down towards the document, they point up, and live in the actual title bar area of the application.

Google Chrome on Windows

The close buttons have been axed and drag handles have been added to the right of each tab. These handles tip users to the fact that tabs can indeed be dragged left or right, or even away from the tab bar to create new windows (a feature introduced in Safari 3). Note, though, that Apple now hides the handle-drag and tab-closing controls until mouseover. In addition to Safari's somewhat clunky ctrl/cmd-shift-brackets shortcuts for switching tabs, Firefox's ctrl-tab shortcut now works as well. Developer Sebastiaan de With has noted that, in the rush to move tabs above the window, Apple somehow forgot to include Safari's trademark in-address-bar progress bar. Oops.

This new tab UI also lends itself to some windowing confusion. While tabs are certainly more defined in a single window, stacking two windows (like we have above) can make it look like a tab in a background window has attached itself in a brain-slug-like fashion.

Unfortunately, the Safari team appears to have found a new love for click-through behavior, as clicking a tab in a background Safari window will bring both that window and tab to the front. This can cause confusion in our example above, but figuring out a safe place to click amid the tiled windows in our example on the right can be even more difficult.

How do you like those transparent tabs, Vista users?

In addition to the tab changes, Apple has scrapped its "unified" or metallic window design on Windows in favor of a far more native UI for XP and Vista users. Apple is now also using standard, native font rendering tools (which should make our EIC Ken Fisher happy), window borders, and toolbars, so Safari should feel more like a native Vista application.

Web standards

Under Safari's hood, Apple claims that a new Nitro engine runs JavaScript up to 30 times faster than IE7, and three times faster than Firefox 3. These comparisons should get more interesting in the near future, though, as Mozilla isn't exactly lying down on the JavaScript job with an upcoming Firefox 3.1 release.

Update: Several Ars readers have e-mailed and tweeted that Apple did indeed compare Safari 4 beta to Firefox 3.1 beta. For these tests, however, Apple heavily promotes VeriTest's iBench 5.0, a discontinued benchmark suite that is highly criticized by John Resig, creator of jQuery and a Mozilla employee, for being outdated and "nearly the worst test suite ever created." Apple also includes SunSpider's JavaScript test, but those results are a far cry from even Apple's "nearly three times as fast" claims over Firefox 3.1 beta 2.

Apple's increasingly popular WebKit rendering engine now supports HTML 5 with offline storage, providing the groundwork for a new generation of Web apps like Gmail to work without an Internet connection. Expanded CSS 3 support is also present, supporting reflections, gradients, and precision masks on websites. Apple also brags that Safari 4 beta is the first browser to pass the Web Standards Project's Acid3 rendering test.

Apple added a number of other lesser features and enhancements to Safari 4 beta, such as a Smart Address Field that suggests and labels URLs from history, bookmarks, and Top Sites. Safari's Google search field now provides suggestions from Google Suggest, though this search box is hard-coded to Google and cannot be customized. Various plug-ins are available for bringing more choices to Safari's search, but we would still like to see Apple—which brags so often about openness and Web standards in its browser—provide search options natively.

Oh, it's a beta

It should go without saying these days, but if you have any Safari plug-ins (nay, InputManagers) installed (1Password and the like), you may need to remove them to run the new version. Safari beta 4 would not stop crashing on startup until we removed 1Password and even Google Gears.

Apple appears to have created a new UI problem for each new feature it introduced, and at least one staff member has already uninstalled Safari 4 beta because of the aforementioned broken plug-in and bookmarklet problems (however, most bookmarklets, including popups, worked fine in our other testing).

Performance is noticeably faster on large, rich media sites like CNN.com, and even resource management seems to have improved. Safari drops to consuming almost none of our CPU resources when idling on a couple of static pages (finally), and its RAM cache actually diminishes a little when closing tabs.

The new tabs UI is an interesting change, but it could definitely use some refinement on both Mac OS X and Vista. While the Top Sites and Cover Flow features initially seemed a bit over the top, they could theoretically be useful for quickly picking out sites. Safari certainly still lacks some key features, most notably an official support for plug-ins support (ahem), but Apple makes up for some of it with a solid and increasingly popular rendering engine and good Mac OS X integration.