Many of you will probably be reading your first review of a VIA CPU; even though the C7 processor has made VIA a name in the world of mobile internet devices and mini-notes their products haven't been of particular interest to the mainstream hardware enthusiast.  Over the past months though VIA and Intel have bunkered up for a battle of extreme low power processors that has developed into the performance review you see here before you.

We first previewed the VIA Isaiah architecture, now known as the VIA Nano processor, in January of 2008 and followed that up with the official unveiling of the Nano processor with even more detail on the CPU design in May.

Architecture Summaries

The two architectures behind the VIA Nano and Intel Atom processors are significantly different from a very technical overview.  One is based on efficiency of performance (Nano) while the other is based on simplicity of performance (Atom).  The VIA Nano Isaiah architecture is much more in line with the design of the Intel Core and AMD Phenom products - it is an out-of-order, superscalar design which utilizes multiple decode and execution units.  Nano takes those performance features and tweaks them for efficiency above all else.  The Intel Atom architecture is much simpler (it uses about 50 million transistors compared to Nano's 94 million) and has a single issue, in-order pipeline that is targeted primary for a target power envelope rather than a performance mark.  Atom does include support for HyperThreading though offering an effect dual-core configuration compared to the VIA Nano's current single-core implementation. 

These are very different products with a surprising amount of overlap in their intended target markets.  VIA's Nano will stretch from mini-notes and UMDs to standard notebooks and optimized desktop PCs.  Intel's Atom processor will be found in small MIDs and will stretch into mini-notes and MAYBE some notebooks, etc. 

I highly encourage you to take a look at our other articles on VIA's Isaiah/Nano processor (here and here) and Intel's Silverthorne/Atom processor (here and here) for more architectural details.  For now we'll be looking at physical products and performance numbers. 

VIA Nano Reference Platform

For testing and evaluating the VIA Nano platform the company provided us with a mini-ITX motherboard from a reference design - this exact product isn't going to be on sale though partners will offer products very similar to it.

  

The mini-ITX platform has officially been adopted by Intel with the Atom products meaning that the VIA-created standard should actually become a standard now -- good news for all.  For those that haven't seen a mini-ITX motherboard yet you'll be scratching your head at seeing such a compressed design.  There are two DDR2 DIMM slots, four SATA channels, one IDE connection and a single PCI Express x16 slot for graphics or other add-in cards. 

On the back of the reference board are a CompactFlash connection (for some solid-state storage action) and a mini PCI slot as well.  These would be GREAT features to have on a retail board as well - I imagine booting off of an 8GB high-speed CF drive and using a standard drive for storage. 

The external connections on the VIA reference board include the standard PS/2 connections, USB ports, serial output, dual NICs and VGA output to use in conjunction with the integrated S3 graphics core on the north bridge.  There are audio connections as well on the right hand side that support up to 6-channels of output. 

Here you can see the VIA 82375 south bridge under a passive heatsink, four SATA channels on the motherboard that all support RAID and the single PCI Express x16 slot that gives the VIA Nano platform such an edge over Intel's Atom for real world user applications.  Without a PCIe slot on the Atom motherboards, OEMs and users are forced to use the inferior integrated Intel IGP or a PCI graphics board, really limiting the possibilities of getting top performance out of the Atom architecture. 

VIA's reference design supports up to 4GB of DDR2-667 MHz memory though the controller is just single channel.

The only power connection on the VIA Nano motherboard is a 20-pin ATX power connector - don't worry your 24-pin power supply connections will work just fine though.

Under that single large heatsink with the fan on it lies the VIA CN896 north bridge chip and the VIA Nano processor; in our case the CPU is the Nano L2100 which operates at 1.8 GHz on an 800 MHz front-side bus with a max TDP of 25 watts. 

The north bridge handles all the PCI/PCIe and memory controller functions and also sports the VIA Chrome9 HC IGP that supports DX9 features.  Nothing to scream about, but it turns out to be faster than Intel's solution.

Here is our classic "chip next to a quarter" image for your perusal - we'll have a better Nano vs. Atom shot a bit later.