VIA C3 Processor 1.0 socket: Socket 370

What the C3 Processor 1.0 is

The VIA C3 Processor 1.0 is a 1000 MHz single-core desktop processor from June 2002. It runs one Centaur Ezra-T core at 1000 MHz with no turbo, so 1 core gives 1 thread. Cache is 64 KB of L2 with 128 KB of L1 on a 130 nm process. Power is typical near 10 W in a Socket 370 ceramic PGA package on a 133 MHz front side bus with a 7.5x multiplier at 1.35 V.

Ezra-T adds copper interconnects over Ezra at the same 64 KB L2, which is why the 1.0 at 1000 MHz holds stability better than late Ezra parts at matching clocks despite sharing the bus. VIA placed the 1.0 in June 2002 with other Ezra-T parts such as the 933 MHz C3 933T. The chip supports MMX, 3DNow and LongHaul power saving.

A 1 GHz clock with a small cache and a 10 W envelope suits quiet Socket 370 desktops with SDRAM and passive cooling. The low voltage keeps heat down in small cases. That is why the 1.0 shipped in fanless office terminals with chipset graphics.

Socket and motherboard compatibility

The Processor 1.0 fits Socket 370 quiet desktops with Ezra-T support. It needs a 370-pin board with a 133 MHz bus and a BIOS that lists VIA C3 Ezra-T parts. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Quiet SDRAM systems are the natural match. Boards listing C3 Processor 1.0 accept the chip with a small 10 W cooler or a passive block with case airflow. Intel-only boards with no VIA entries may refuse the different CPUID string, so the support list decides.

Memory, PCIe and cooling

Memory is PC100 and PC133 SDRAM through the board chipset, matched to the board DIMM sockets. The CPU has no memory controller, so the chipset sets the type and speed. Apollo boards commonly run PC133 pairs for 133 MHz Ezra-T parts.

A 133 MHz front side bus ties the CPU to the chipset, while AGP and PCI hang off the chipset. No PCIe lanes originate on the die. Cooling uses the Socket 370 lug clip with a cooler rated for 10 W. A passive block works when case air moves across the fins.

Upgrade paths

On the same socket, a move to a C3 Processor 1.0A such as VIA C3 Processor 1.0A keeps the board and memory when the support list names it. The 1.0A uses a 100 MHz bus with a 10x multiplier for the same 1000 MHz, so board bus tables must include the 100 MHz path. A C3 800A such as VIA C3 800A drops 200 MHz at lower power and is a step down.

A move to Nehemiah C3 parts keeps Socket 370 with SSE support when the BIOS lists C5XL strings. The Socket 370 page lists the Tualatin to Nehemiah range for planning.