Socket AM3+

Socket AM3+ is a modification of Socket AM3, which was released on February 9, 2009. AM3+ was released in mid-2011^[1] designed for CPUs which use the AMD Bulldozer microarchitecture and retains compatibility with processors made for AM3.^[2] The Vishera line of AMD CPUs also all use Socket AM3+. It is the last AMD socket for which Windows XP support officially exists.

Socket AM3+

Release date	October 2011
Type	PGA-ZIF
Chip form factors	PGA
Contacts	942 (Socket) 938 (Socket AM3 CPU) 940 (Bulldozer Based CPU)
FSB protocol	HyperTransport 3.1
FSB frequency	200 MHz System clock HyperTransport up to 3.2 GHz
Processors	Phenom II Athlon II FX Opteron
Predecessor	AM3
Successor	AM4
Memory support	DDR3
This article is part of the CPU socket series

Technical specifications

The AM3+ Socket specification contains a few noteworthy design changes over its AM3 predecessor. The 942 pin count for the AM3+ is an increase of one compared to the AM3 Socket layout.^[3] The AM3+ Socket has larger pin socket diameter of 0.51 mm compared to 0.45 mm with the AM3 Socket. There is a faster serial link of 3400 kHz from the CPU to the power controller, compared to 400 kHz. The AM3+ Socket offers improved power regulation and power quality specifications, including an increased maximum current support of 145 A versus 110 A. There is also a redesigned CPU cooler retention harness allowing for slightly better airflow for CPU cooling, while retaining cooler backward compatibility.^[4]

Compatibility

Processors accepted by the AM3+ socket

The 942-contact AM3+ socket accepts both the 940-pin AM3+ CPU and the 938-pin AM3 CPU. This backward compatibility is intentional.

Motherboards that can accept the AM3+ processor

AM3+ CPUs are not mechanically compatible with AM3 sockets as AM3+ CPUs have an additional pin that the AM3 socket can not accommodate. However, some manufacturers have found success in retrofitting AM3-technology motherboards for AM3+ processors by replacing the AM3 socket with AM3+ and providing a BIOS upgrade. This is called "AM3+ Ready".^[5] Potential incompatibilities with new AM3+ features include:

• Sideband temperature sensor interface for reading the temperature from the CPU. Without knowing the temperature, CPU PWM fan headers may only run at full speed.
• Certain power-saving features may not work, due to lack of support for rapid V_CORE switching.^[6]

While AM3+ CPUs can be inserted into AM2 or AM2+ sockets, AM3+ CPUs could not operate in motherboards designed for AM2+ or AM2 CPUs. These motherboards are designed for DDR2 memory but AM3+ CPUs only have a DDR3 memory controller.

Heatsink

The 4 holes for fastening the heatsink to the motherboard are placed in a rectangle with lateral lengths of 48 mm and 96 mm for AMD's sockets Socket AM2, Socket AM2+, Socket AM3, Socket AM3+, Socket AM4, Socket AM5, Socket FM2, Socket FM2+, Socket FM1 and Socket AM1. Cooling solutions should therefore be interchangeable.

See also

• List of AMD FX microprocessors
• List of AMD chipsets