Best free antivirus for netbook (waiting for dual core Atom...)

See also: Free anti malware/anti spyware protection for netbooks

Antivirus software run smoothly, almost transparently, on dual and quad core processors. Intel Atom processors for netbooks are dimensioned for basic browsing experience, even the newest generation of Intel Atom processors (Atom N450 and N470) didn't bring a significant performance boost.
The game will definetly change with dual core Atom (N550, coming up summer 2010). In any case most of the Windows based netbooks sold in 2010 will have a single core Atom processor, for this reason you should be careful in choosing an antivirus software, avoid antivirus that produce a heavy CPU load... you don't want to slow down an already slow system!
The German magazin C't benchmarked 7 free antivirus suites

• Avast Free Antivirus
• AVG Anti-Virus Free Edition
• Avira AntiVir Personal
• Comodo Antivirus Free
• Microsoft Security Essentials
• Panda Cloud Antivirus
• Rising Antivirus 2010

The test result: only Avast, Avira and Panda antivirus are light enough to run on netbooks without significant system slow down while antivirus from Microsoft, Comodo and Rising resulted in a significant slow down of the netbooks.
Of the three "fast free antivirus" Avast provide the best protection since a Web Filter is included.

A major problem with free antivirus software is the "slow" update rate: once a day for the free antivirus vs a couple of hours for most of the commercial antivirus programs.
It is up to you to decide whether or not to invest 40-50 USD / year in a commercial security suite or to just use free antivirus. In any case you shouldn't miss a Web Filter function to avoid infections from malicious websites.

See also: Free anti malware/anti spyware protection for netbooks

Benchmarks Atom vs iPad A4 vs iPhone 3GS ARM Cortex and much more...

See update here

With the iPad, Apple is creating a new type of device that got some similarities with the actual netbooks. It is known that the iPad got an Apple A4 processor clocked at 1GHz, it isn't clear yet which type of ARM core is really used: Cortex A8, A9, a customized version? It is very interesting to understand how this new processor compare to other ARM processors (ARM11 in iPhone 3G and Cortex A8 in iPhone 3GS) and to the Intel Atom processors.
It is really tough to compare performance of CPU with different architecture, running different operating systems and especially targeting very different applications.
Since years ARM claims superior performance for the Cortex A8 and A9 compared to Intel Atom. Now I could not resist, especially because the benchmarking race started and I finally got a critical mass of benchmarking data on Atom vs ARM performance.

First of all a clarification: here we talk about benchmarking of CPU cores, it has little to do with comparing performance of the iPhone vs iPad or iPad vs netbooks. If you want to compare two devices you have to find first a common use case and metrics to measure it, for example Anandtech published browsing benchmarks showing that ARM Cortex cores in iPhone 3GS and iPad are much slower than Atom in one of the most important use cases: Internet browsing.

The benchmarking ARM vs Atom race started and I finally got a critical mass of benchmarking data: ARM, the Linley group and the german magazine C't published CoreMark benchmarks for many ARM cores and Intel Atoms.
EEMBC CoreMark is a good metrics of the pure processing power of the CPU core, the algorithm is pretty small and fits in level 1 cache. CoreMark basically replaces the old Million Instruction Per Second (also called as MIPS, not to be exanged with the MIPS company ain direct competition with ARM...)

I created a chart with normalized CoreMark/MHz for each of the result I got.
The result for Atom processors seems stable around 2,5-2,8 CoreMark/MHz, I don't have a clear bottom line for the Cortex processors. The best results for Cortex A8 and A9 probably derive from tests done in best case conditions in development boards (e.g. for TI OMAP, Freescale i.MX515 and Samsung S5PC110) while real life products (such as iPhone and iPad) got much lower results.
Until the test conditions are clarified is not possible to state who really wins!!