VIA C7
Encyclopedia
The VIA C7 is an x86 central processing unit
designed by Centaur Technology
and sold by VIA Technologies
.
cores but is nearly identical to the latest VIA C3 Nehemiah core. The C7 was officially launched in May 2005, although according to market reports, full volume production was not in place at that date. In May 2006 Intel's cross-licensing
agreement with VIA expired and was not renewed, which was the reason for the forced termination of C3 shipments on March 31, 2006, as VIA lost rights to the socket 370. The C7 appears still to be found in the marketplace, for example, on the bargain-priced Everex
TC2502, sold by Wal-Mart
with a Linux distribution
preinstalled and on the HP Mini-Note.
A 1 GHz C7 processor with 128kB of cache memory is used in VIA's own PX10000G motherboard
which is based on the proprietary Pico-ITX
form factor. The chip is cooled by a large heatsink that covers most of the board and a small 40mm fan.
In early April 2008 the schoolroom-use oriented, ultra-portable HP 2133 Mini-Note PC
family debuted with an entirely VIA-based, 1.0, 1.2 and 1.6 GHz C7-M processor portfolio, where the lowest speed model is optimized for running an SSD-based 4GB Linux
distribution with a sub $500 price tag, while the middle tier carries Windows XP
and the top model comes with Windows Vista
Business, factory default. HP chose the single-core VIA C7-M CPU in order to meet the already fixed ??$ 499 starting price, even though Intel's competing Atom processor line debuted on the 2nd of April, 2008.
The C7 is sold in three main versions:
line-up.
New Features of this core include:
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
designed by Centaur Technology
Centaur Technology
Centaur Technology is an x86 CPU design company, now a wholly owned subsidiary of VIA Technologies, a member of the Formosa Plastics Group, Taiwan's largest industrial conglomerate.-History:...
and sold by VIA Technologies
VIA Technologies
VIA Technologies is a Taiwanese manufacturer of integrated circuits, mainly motherboard chipsets, CPUs, and memory, and is part of the Formosa Plastics Group. It is the world's largest independent manufacturer of motherboard chipsets...
.
Product history
The C7 delivers a number of improvements to the older VIA C3VIA C3
The VIA C3 is a family of x86 central processing units for personal computers designed by Centaur Technology and sold by VIA Technologies. The different CPU cores are built following the design methodology of Centaur Technology.-Samuel 2 and Ezra cores:...
cores but is nearly identical to the latest VIA C3 Nehemiah core. The C7 was officially launched in May 2005, although according to market reports, full volume production was not in place at that date. In May 2006 Intel's cross-licensing
Cross-licensing
A cross-licensing agreement is a contract between two or more parties where each party grants rights to their intellectual property to the other parties.-Patent law:...
agreement with VIA expired and was not renewed, which was the reason for the forced termination of C3 shipments on March 31, 2006, as VIA lost rights to the socket 370. The C7 appears still to be found in the marketplace, for example, on the bargain-priced Everex
Everex
Everex is a manufacturer of desktop and notebook personal computers. It was established in 1983 and headquartered in Fremont, California. The company was founded by Steve Hui, John Lee and Wayne Cheung. In 1988, Everex was the leader in tape backup sales with half the world market...
TC2502, sold by Wal-Mart
Wal-Mart
Wal-Mart Stores, Inc. , branded as Walmart since 2008 and Wal-Mart before then, is an American public multinational corporation that runs chains of large discount department stores and warehouse stores. The company is the world's 18th largest public corporation, according to the Forbes Global 2000...
with a Linux distribution
Linux distribution
A Linux distribution is a member of the family of Unix-like operating systems built on top of the Linux kernel. Such distributions are operating systems including a large collection of software applications such as word processors, spreadsheets, media players, and database applications...
preinstalled and on the HP Mini-Note.
A 1 GHz C7 processor with 128kB of cache memory is used in VIA's own PX10000G motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
which is based on the proprietary Pico-ITX
Pico-ITX
Pico-ITX is a PC motherboard form factor announced by VIA Technologies in January 2007 and demonstrated later the same year at CeBIT. The formfactor was transferred over to SFF-SIG in 2008. The Pico-ITX form factor specifications call for the board to be 10 × 7.2 cm , which is half the area...
form factor. The chip is cooled by a large heatsink that covers most of the board and a small 40mm fan.
In early April 2008 the schoolroom-use oriented, ultra-portable HP 2133 Mini-Note PC
HP 2133 Mini-Note PC
The HP 2133 Mini-Note PC is a full-function netbook aimed at the business and education markets. It is available with SUSE Linux Enterprise Desktop, Windows Vista or Windows XP. Its retail price starts at US$499 for the Linux version with 4GB of flash memory. According to DigiTimes, the netbook is...
family debuted with an entirely VIA-based, 1.0, 1.2 and 1.6 GHz C7-M processor portfolio, where the lowest speed model is optimized for running an SSD-based 4GB Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
distribution with a sub $500 price tag, while the middle tier carries Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
and the top model comes with Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
Business, factory default. HP chose the single-core VIA C7-M CPU in order to meet the already fixed ??$ 499 starting price, even though Intel's competing Atom processor line debuted on the 2nd of April, 2008.
The C7 is sold in three main versions:
- C7: for desktops / laptops (1.5-2.0 GHz) - FCPGA Pentium-M package, 400, 533, 800 MHz FSB
- C7-M: for mobiles / embedded (1.5-2.0 GHz) - NanoBGA2, 21mmx21mm, 400, 800 MHz FSB
- C7-M Ultra Low Voltage: for mobiles / embedded (1.0-1.6 GHz) - NanoBGA2, 21mmx21mm, 400, 800 MHz FSB
- C7-D: similar to original C7, but RoHS-compliant and marketed as "carbon-free processor". Some variants do not support PowerSaver
Esther
The Esther (C5J) is the next evolution step of the Nehemiah+ (C5P) core of the VIA C3VIA C3
The VIA C3 is a family of x86 central processing units for personal computers designed by Centaur Technology and sold by VIA Technologies. The different CPU cores are built following the design methodology of Centaur Technology.-Samuel 2 and Ezra cores:...
line-up.
New Features of this core include:
- Average power consumption of less than 1 watt.
- 2 GHz operation and a TDPThermal Design PowerThe thermal design power , sometimes called thermal design point, refers to the maximum amount of power the cooling system in a computer is required to dissipate. For example, a laptop's CPU cooling system may be designed for a 20 watt TDP, which means that it can dissipate up to 20 watts of heat...
of 20 watts. - L1 cache reduced from 32k instruction + 32k data to 16k instruction + 16k data, L2 cache increased from 64k to 128k, with associativity increased from 16-way set associative in C3 to 32-way set associative in C7.
- VIA has stated the C7 bus is physically based upon the Pentium-M 479-pin packaging, but uses the proprietary VIA V4 bus for electrical signalling, instead of Intel’s AGTL+ Quad Pumped Bus, avoiding legal infringement.
- "Twin Turbo" technology, which consists of dual PLLsPhase-locked loopA phase-locked loop or phase lock loop is a control system that generates an output signal whose phase is related to the phase of an input "reference" signal. It is an electronic circuit consisting of a variable frequency oscillator and a phase detector...
, one set at a high clock speed, and the other set at a lower speed. This allows the processor's clock frequency to be adjusted in a single processor cycle. Lower switching latency means that more aggressive regulation can be employed. - Support for SSE2SSE2SSE2, Streaming SIMD Extensions 2, is one of the Intel SIMD processor supplementary instruction sets first introduced by Intel with the initial version of the Pentium 4 in 2001. It extends the earlier SSE instruction set, and is intended to fully supplant MMX. Intel extended SSE2 to create SSE3...
and SSE3SSE3SSE3, Streaming SIMD Extensions 3, also known by its Intel code name Prescott New Instructions , is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU...
extended instructions. - NX bitNX bitThe NX bit, which stands for No eXecute, is a technology used in CPUs to segregate areas of memory for use by either storage of processor instructions or for storage of data, a feature normally only found in Harvard architecture processors...
in PAEPhysical Address ExtensionIn computing, Physical Address Extension is a feature to allow x86 processors to access a physical address space larger than 4 gigabytes....
mode that prevents buffer overflowBuffer overflowIn computer security and programming, a buffer overflow, or buffer overrun, is an anomaly where a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory. This is a special case of violation of memory safety....
software bugs from being exploitable by viruses or attackers. - Hardware support for SHA-1 and SHA-256 hashing.
- Hardware based "Montgomery multiplierMontgomery reductionIn arithmetic computation, Montgomery reduction is an algorithm introduced in 1985 by Peter Montgomery that allows modular arithmetic to be performed efficiently when the modulus is large ....
" supporting key sizes up to 32K for public-key cryptographyPublic-key cryptographyPublic-key cryptography refers to a cryptographic system requiring two separate keys, one to lock or encrypt the plaintext, and one to unlock or decrypt the cyphertext. Neither key will do both functions. One of these keys is published or public and the other is kept private...
.
Design choices
- C7 Esther as an evolutionary step after C3 Nehemiah, in which VIA / Centaur followed their traditional approach of balancing performance against a constrained transistor / power budget.
- The cornerstone of the C3 series chips' design philosophy has been that even a relatively simple in-order scalar core can offer reasonable performance against a complex superscalar out-of-order core if supported by an efficient "front-end", i.e. prefetch, cache and branch prediction mechanisms.
- In the case of C7, the design team have focused on further streamlining the (front-end) of the chip, i.e. cache size, associativity and throughput as well as the prefetch system. At the same time no significant changes to the execution core (back-end) of the chip.
- The C7 successfully further closes the gap in performance with AMD / Intel chips, since clock speed is not thermally constrained.
See also
- List of VIA C7 microprocessors
- List of VIA Eden microprocessors
- List of VIA microprocessors
- Intel AtomIntel AtomIntel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, embedded application ranging from health care to advanced robotics and Mobile Internet devices...
- NetbookNetbookNetbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...
- Comparison of subnotebooksComparison of subnotebooksThis page is a comparison of various subnotebooks, in various categories. See also the comparison of netbooks, as there is significant overlap between these categories.- Subnotebooks :These are examples of recent subnotebooks, not necessarily UMPCs....
External links
- An inside look at the VIA C7-M, by Van Smith
- Review of the EPIA EN15000 with VIA C7 Processor
- VIA C7 Processor
- VIA C7-M Processor
- Detailed Platform Analysis in RightMark Memory Analyzer. Part 12: VIA C7/C7-M Processors, translated in English
- http://www.cpushack.net/VIA.html
- http://www.digit-life.com/articles/viacyrix3/
- http://www.sandpile.org/impl/c5xl.htm