First introduced in beta in April, Panda Cloud Antivirus graduates to a stable, public release and signifies a major security vendor taking aim at the freeware competition--instead of the other way around. Cloud Antivirus was notable on its beta release for being one of the few security options available to users that contained most of its protections in the cloud. This allowed it to protect users while consuming significantly fewer resources than many competing programs.

Panda Cloud Antivirus 1.0 is notable as a free security solution for two reasons: Panda is a reputable security vendor, and the program achieves its goal of freeing up system resources. In a press release, Panda Security CEO Juan Santana described Cloud Antivirus as a game-changer. It's not clear quite yet that that's the case, but at the very least the program looks to fill a niche created by resource-conscious netbooks.

As light on resources as advertised, Cloud Antivirus offers strong reputation-based protection for those who want their security program out of sight and out of mind. A third-party efficacy evaluation wasn't available at the time of writing, but in empirical testing the program only used 9 MB of RAM while idle, and only 56 MB of RAM when scanning. Many other security programs will run scans at 150 MB of RAM or more.

Despite keeping most of its database in the cloud, Panda Security's Senior Research Advisor, Pedro Bustamante, noted during an interview in October that Cloud Antivirus isn't disabled just because the host computer is disconnected from the Internet. "Panda has an offline mode that uses a small cached copy of Collective Intelligence on your local drive, it's only the most recent threats on a real time wild list." Collective Intelligence is the name that Panda gave its cloud system when it was introduced in 2007.

When you open Cloud Antivirus, the main window lets you know whether you're safe or not with a big red or green icon. Cloud Antivirus works as other antivirus solutions do, offering a Quick Scan and a Custom scan for specific folder, files, and drives, but its ancillary features are exceptionally light. The Quick Scan took 13 minutes on my Windows 7 Lenovo T400 laptop.

Dragging an active Cloud Antivirus window, in Windows 7 at least, will turn it translucent. (Credit: Screenshot by Seth Rosenblatt/CNET)

You can opt out of contributing anonymous data to the cloud, but that also opts you out of automatic threat management. There's a network connection proxy option should you need it, and a reporting feature that will show you what kind of threats have been detected and removed from your computer. You can filter the report by All, Last 24 hours, Last Week, or Last Month, and there's a Recycle Bin pane from which you can recover a false positive, should you need it. Unfortunately, the Recycle Bin is hidden behind an obnoxious "flipping" screen that cheesily rotates when you need to access it.

If you're familiar with the minimalist Microsoft Security Essentials, Cloud Antivirus is even simpler. I did notice some odd interface rendering around the minimize and close buttons in Windows XP, but not in Windows 7. There are other more serious concerns about the program. Most notably, it lacks a scheduler, and it removes user input from update functions. Scans are also limited: you can tell the program what to scan, but not what to look for, so forget about toggling heuristics or rootkits. Then again, the point of this kind of security is that it's all wrapped into one.

Keeping in mind its limited feature set, and that we don't have efficacy numbers at the time of reviewing, Panda Cloud Antivirus makes good security choice for those willing to take the plunge.