AMD FX-4100 socket: AM3+

What the FX-4100 is

AMD FX-4100 is a quad core Zambezi processor that AMD released in October 2011 for socketed desktops. It uses the Bulldozer core design on a 32 nm process, running at 3.6 GHz base with Turbo Core to 3.8 GHz. The chip holds two Bulldozer modules with four threads, 4 MB of L2 with 2 MB per module, and 8 MB of shared L3. Power is 95 W. All FX parts ship with an unlocked Black Edition multiplier. The retail box carries part number FD4100WMW4KGU. The Orochi die holds about 1.6 billion transistors on 319 mm², with 16 KB of L1 data per core plus 64 KB of L1 instructions per module. The unlocked multiplier spans 4x to 19x on a 200 MHz reference clock.

Two modules with shared floating point units cover threaded home work and light games of the period. Turbo Core 2.0 lifts half loaded work to the maximum rate while full loads sit lower. The 1.6 billion transistor die measures 319 mm².

Towers pair it with 970, 990X or 990FX boards, 4 GB to 8 GB of DDR3 and a discrete card. Fixed 3.6 GHz clocks with multiplier headroom suit both stock and tuned builds. The 200 MHz reference clock with a 4x to 19x range leaves room past stock on boards with strong delivery. The How to find your CPU socket type guide shows how to confirm the socket.

Socket and motherboard compatibility

The FX-4100 drops into AM3+ on 9 series boards with Zambezi support. The 942-pin socket accepts 940-pin AM3+ chips plus 938-pin AM3 chips with DDR3 only. The 9 series launched in June 2011 for this socket, while 8 series boards carry AM3 chips only.

An AM3+ chip never fits an AM3 board, since the extra pin blocks seating, except rare vendor retrofits that swapped the socket with broken temperature sensing. Check the maker CPU list for the exact board BIOS. Southbridge chips SB950 or SB920 handle SATA and USB around the CPU, with SLI plus CrossFireX multi GPU support on 990FX boards and AMD OverDrive tuning software. The Socket vs chipset: what decides whether a CPU works guide covers AMD pairing rules.

Memory, PCIe and cooling

Memory support is DDR3 up to 1866 MT/s, two channels, up to four DIMMs. Two matched modules give the rated bandwidth for four threads. HyperTransport 3.0 links tie the CPU to the chipset at up to 5200 MT/s. The Southbridge SB950 or SB920 handles SATA and USB around the CPU.

PCI Express slots come from the 9 series chipset with PCIe 2.0 for graphics and expansion. A mainstream card of the era pairs without waste, while 990FX boards suit two card builds.

Cooling follows the 95 W rating with a stock heatsink or tower cooler. Multiplier tuning through AMD OverDrive wants headroom beyond stock.

Upgrade paths

Within Socket AM3+ the FX-4100 can move to six and eight core Zambezi or Vishera parts on the same board, where the BIOS lists them. Memory, storage and the graphics card carry over. A six core step is the FX-6100 class on the same socket.

A platform move to DDR4 sockets needs a new board and RAM. The AM3+ tower keeps value for tuned duty where the unlocked multiplier still gives room past stock. Keep the AM3+ tower for tuned duty where the unlocked multiplier still gives room.