Now it's time to take a look at the competitor to Atom. While Intel was hoping that it would only have to deal with C7, VIA had other ideas. At Computex, the very same place Intel revealed Atom to the world, VIA introduced Nano. VIA's aim for Nano is the same as Atom, it's designed to replace the C7 as the top of the energy efficient heap while improving its overall processing power.
VIA sent us their reference design Nano platform which is simply a VIA EPIA-SN that we reviewed not long ago, but the C7 was removed and the Nano added. That's the beauty of Nano, it's totally pin compatible with C7, so any board running a C7 can simply have a Nano added in its place; no other changes apart from a BIOS update is needed.
While Intel went with a single phase voltage regulation system for the Atom, VIA adds in three phases. While it's not needed, it allows the board to run even cooler as the components don't have to do as much work. In fact, with three phases we didn't get a heat reading off the voltage units above 28 degree Celsius; a very impressive result.
To VIA's advantage, they have managed to do away with the old PCI interface and have a single PCI Express x16 slot supporting PCI-E 2.0, which means you can use any PCI-E devices in it or simply go with a dedicated graphics card taking more load off the CPU and IGP.
But that's not all. If you are one to want wireless networking, a mini-PCI slot is located on the back of the board, which can connect any mini-PCI device, including TV tuners. So, you're good to go here. Also on the back is a Compact Flash media slot. If you really want to, you can use this as a boot device with Windows or Linux Installed on it, reducing boot times significantly, especially with a 266X CF card. Imagine booting XP in just under 8 seconds in a nice compact little unit.
VIA's Nano CPU is a new architecture built on what was already known from the C7, but with new power management technologies and a totally new way of going. The Nano is an out-of-order processor, like the Core 2 and Phenom, allowing it to process instructions out of a specific order to achieve the same end result. This gives the CPU a boost when compared to the older in-order design which the C7, C3 and Atom are based on.
To match the Atom's 64-bit capabilities, VIA has also added X86-64 instruction sets to allow the Nano to work under XP 64 and Vista 64, so no one is missing out when buying a Nano over Atom. One thing that VIA has over the Atom is a 128-bit wide instruction execution engine, similar to what the Core 2 based on the Penryn architecture has. This allows the CPU to complete a single SIMD instruction in 1 clock cycle, where the Atom needs 2 cycles to do the same instruction, allowing the Nano to move to the next instruction where Atom is still on the end of the first.
Nano is based on a 65nm process, which is larger than what Intel is currently using. However, its TDP is only 25watts at 2GHz, which is better than the Atom which uses 25watts at 1.6GHz. Since the CPU is pin compatible with the C7, it uses the same V4 bus or the P4 bus as it's actually known. It's the same bus that Core 2, Pentium 4 and Pentium-M all share. The current generation run at 800MHz FSB, where future generations can increase to 1333MHz. On the cache side of things, VIA has it all over Intel once again with 64K L1 cache and a total of 1MB of L2 cache.
Last on the list is something we would have expected to see in high-end CPUs, but VIA has gone and added it to the Nano; that being Virtualisation Technology or Vanderpool Technology as it's known from Intel. This allows the CPU to do hardware emulation for Virtual PCs, giving V-PCs a better feel and response time.
To match up the VIA Nano for maximum experience, VIA has used its newest chipset, the CN896 Northbridge. This chipset was used for the EPIA-SN and C7 combination; it not only adds support for the C7 and Nano, it also has a dual channel memory controller for DDR2 modules, allowing for a total of 4GB of memory in a 128-bit array; a far better approach to the Atom series. Not only this, but a PCI Express 2.0 bus for the single graphics card slot give it the latest in PCI-E speeds, allowing new generation graphics cards to be used at their full speed. The CN896 also incorporates an IGP from S3 called the Chrome9 HC. This IGP also lacks DX10 support but does include on-die decoding of HD video in 720p; a big advantage for HTPC users, that's for sure. Unfortunately, the EPIA-SN doesn't include any DVI or HDMI output, but this could be changed in later revisions.
VIA's newest Southbridge, the VT8251 finally replaced the VT8237A which has lingered around for too long. The VT8251 finally adds four SATA II ports, PCI Express connectivity (which is used for the onboard Gigabit LAN) as well as HD audio. This is another advantage to VIA Nano; it has HD audio support and uses it.