AMD K6-III+ 450ACZ socket: Super Socket 7

What the K6-III+ 450ACZ is

The AMD K6-III+ 450ACZ is a 450 MHz single-core processor from April 2000. It runs one K6 Sharptooth core at 450 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 with part number 450ACZ on a 100 MHz front side bus with a 4.5x multiplier at 2.0 V.

Mobile binning with PowerNow support separates ACZ parts from desktop 250 nm K6-III parts at 20 W, which is why the 450ACZ at 450 MHz runs far cooler than K6-III 450 desktop parts at matching clocks. AMD launched the 450ACZ on April 18, 2000 at $140. The chip supports MMX, 3DNow+, PowerNow and CMPXCHG8B.

A 450 MHz clock with a full cache and a 12 W envelope suits quiet Super Socket 7 desktops with SDRAM and small coolers. The 4.5x ratio is standard for 100 MHz boards. That is why the 450ACZ shipped as a cool office upgrade.

Socket and motherboard compatibility

The 450ACZ fits Super Socket 7 quiet 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.

Quiet SDRAM towers are the natural match. Boards listing 450ACZ accept the chip with a 12 W cooler. Older 66 MHz boards with no 100 MHz tables cannot feed the ratio.

Memory, PCIe and cooling

Memory is EDO DRAM and SDRAM through the board chipset, matched to the board sockets. The CPU has no memory controller. Quiet ALi Aladdin boards commonly run PC100 pairs.

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 12 W cooler.

Upgrade paths

On the same socket, a move to a K6-III+ 500ACZ keeps the board for 50 MHz more at equal power. A K6-2+ 450ACZ halves cache to 128 KB at 13 W for slightly higher power. A K6-III+ 475ACZ splits the gap at 475 MHz.

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