VIA made quite a splash early this year when they announced the Isaiah CPU architecture, which was developed at their Centaur design center. At the time of the announcement, we spoke with VIA's Centaur design center president, Glenn Henry, to get a deeper insight into what VIA had in store with Isaiah, but we weren't given many hard details regarding final clock speeds and specifications, performance, branding, or availability.
Today though, VIA is ready to disclose a few more details regarding the Isaiah CPU architecture. First off, Isaiah-based processors now fall under the Nano brand. Due to their low-power design, VIA's Nano processors will initially be used to power a broad range of thin and light notebooks, but they will also appear in ultra mobile, mini-note type devices and small form factor, energy efficient "green" desktop systems as well. If you look back at our interview with Glenn Henry, we answer many questions regarding VIA's Nano processors and have an architectural FAQ posted at the end. To reiterate some of what we cover in that piece, the VIA Nano is the first 64-bit, superscalar, speculative out-of-order processors in VIA’s x86 product line-up. It leverages Fujitsu’s 65nm process technology for enhanced power efficiency despite having roughly twice the numbers of transistors as the 90nm-based VIA C7 processor.
Although the chips are being manufactured at 65nm, Nano processors have a larger die than C7, mostly due to the Nano having roughly 8x the amount of total cache. VIA Nano processors have a die size of 7.650mm x 8.275mm, or about 63 square mm, versus the 32 square mm of the 90nm-based C7. Nano processors use the same packaging, however, VIA's compact 21mm x 21mm NanoBGA2 package.
As you can see in the chart above, VIA's Nano processors will initially be offered in five different skus, two “Low Voltage” versions, the L2100 and L2200, and three “Ultra Low Voltage” versions, the U2400, U2500, and U2300.
According to the specifications, initial production versions of the 1.0GHz VIA Nano ULV processor will have a maximum Thermal Design Power (TDP) of 5 watts with an idle power of just 100mW. At the other end of the spectrum is the 1.8 GHz VIA Nano processor a 25 watts TDP and 500mW idle power rating.
This high-level block diagram gives a basic architectural overview of the VIA Nano processor. Other features of the design include:
- 64-bit Superscalar Speculative Out-Of-Order MicroArchitecture: Supports a full 64-bit instruction set and provides for macro-fusion and micro-fusion functionality, and sophisticated branch prediction for greater processor efficiency and performance.
- High-Performance Computation and Media Processing: The high-speed, low power VIA V4 Front Side Bus starting at 800MHz, plus a high speed floating point unit, support for new SSE instructions, and two 64KB L1 caches and 1MB exclusive L2 cache with 16-way associativity gives a big boost to multimedia performance.
- Advanced Power and Thermal Management: Aggressive management of active power includes support for the new “C6” power state, Adaptive PowerSaver Technology, new circuit techniques and mechanisms for managing the die temperature, reducing power draw and improving thermal management.
- Scalable Upgrade to VIA C7 Processor: Pin-to-pin compatibility with current VIA C7 processors enables a smooth transition for OEMs and mainboard vendors, enabling them to offer a wider range of products for different markets with a single board or system design.
- Greener Technology: In addition to full compliance with RoHS and WEEE regulations, product manufacturing will be halogen-free and lead-free at launch, helping to promote a cleaner environment and more sustainable computing.
- Enhanced VIA PadLock Security Engine: Industry-leading on-die hardware cryptographic acceleration and security features, including dual quantum random number generators, an AES Encryption Engine, NX execute protection, and SHA-1 and SHA-256 hashing.
VIA is also quick to make a comparison of the security features offered in the latest x86 processors. As the above chart shows, the Nano has a number of cryptographic acceleration and security features integrated into the CPU die, which Intel and AMD do not.
Please note, the benchmark results posted above comparing the VIA Nano and C7 processor were provided by VIA to show the comparative performance of the two processors when coupled with the new VIA VX800 digital media IGP chipset. A variety of applications were tested, grouped into three main categories - productivity, multimedia, and synthetics.
As the numbers show, the Nano offers about 1.6x to 3.2x the performance of the C7 clock-for-clock while within a similar, albeit somewhat higher, power envelope.
VIA also provided a Performance Per Watt comparison between a 1.6GHz Intel Celeron-M 520 and a 1.6GHz VIA Nano. The test was based on the overall score from an OfficeBench 2007 benchmark run and the TDP for a 1.6GHz Celeron-M (31 watts) versus the TDP of a 1.6GHz VIA Nano (17 watts). As per VIA's results, the Nano offers 1.9x the perf per watt of a similarly clocked Celeron M. We hope to verify these results four ourselves, sometime in the near future.
According to VIA, Nano processors are available now for OEMs and motherboard vendors, and systems featuring VIA Nano processors should hit the market in Q3 2008.