AMD K6-III+ 500ACZ socket: Super Socket 7

What the K6-III+ 500ACZ is

The AMD K6-III+ 500ACZ is a 500 MHz single-core desktop processor from April 2000. It runs one K6 Sharptooth core at 500 MHz with no turbo, so 1 core gives 1 thread. Cache is 256 KB of full-speed on-chip L2 with 64 KB of L1 on a 180 nm process with 21 million transistors. Power is rated at 12 W in a Super Socket 7 CPGA package on a 100 MHz front side bus with a 5x multiplier at 2.0 V.

Sharptooth shrinks the K6-III core to 180 nm with PowerNow support, which is why the 500ACZ at 500 MHz runs far cooler than 250 nm K6-III 450 parts at 20 W despite higher clocks. AMD sold ACZ mobile-binned parts into desktop Super Socket 7 boards with BIOS updates. The chip supports MMX, 3DNow+, PowerNow and CMPXCHG8B.

A 500 MHz clock with on-chip cache and a 12 W envelope suits late Super Socket 7 towers with SDRAM and AGP graphics. The low voltage keeps small cases quiet. That is why the 500ACZ shipped as a drop-in speed lift for MVP3 boards.

Socket and motherboard compatibility

The 500ACZ fits Super Socket 7 late desktops with Sharptooth support. It needs a 321-pin board with a 100 MHz bus and a BIOS that lists K6-III+ parts. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Late SDRAM towers with MVP3 and MVP4 paths are the natural match. Boards listing K6-III+ 500ACZ accept the chip with a 12 W clip cooler. Older 66 MHz-only boards with no 100 MHz tables cannot feed the 5x ratio, so the support list decides.

Memory, PCIe and cooling

Memory is EDO DRAM and SDRAM through the board chipset, matched to the board DIMM sockets. The CPU has no memory controller. Late MVP3 boards commonly run PC100 SDRAM pairs for 100 MHz Sharptooth parts.

A 100 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 lug clip with a cooler rated for 12 W.

Upgrade paths

On the same socket, a move to a K6-III+ 475ACZ keeps the board when a slower spare matters, while a K6-2+ 570ACZ such as AMD K6-2+ 570ACZ trades cache size for clocks at higher power. The 570ACZ halves L2 to 128 KB while adding 70 MHz. A K6-III+ 450ACZ such as AMD K6-III+ 450ACZ drops 50 MHz at equal power.

A move to Slot A Athlon needs a new board. The Super Socket 7 page lists the Sharptooth range for planning.