Socket T

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Socket T
Specifications
Type	LGA
Chip form factors	Flip-chip land grid array
Contacts	775
Bus Protocol
FSB	533 MT/s, 800 MT/s, 1066 MT/s, 1333MT/s
Voltage range
Processors	Intel Pentium 4 (2.66 - 3.80 GHz) Intel Celeron D (2.53 - 3.6 GHz ) Intel Pentium 4 Extreme Edition  (3.20 - 3.73 GHz) Intel Pentium D (2.66 - 3.60 GHz) Intel Pentium Extreme Edition  (3.20 - 3.73 GHz) Intel Core 2 Duo (1.60 - 2.67 GHz) Intel Core 2 Extreme (2.66 - 2.93 GHz) Intel Core 2 Quad (2.4 GHz)
This article is part of the CPU socket series

Socket T, also known as LGA775, is Intel's latest desktop CPU socket. LGA stands for Land Grid Array. The word "socket" is now a misnomer, because an LGA775 motherboard has no socket holes, instead it has 775 protruding pins which touch contact points on the underside of the processor (CPU).^[1]

The Prescott and Cedar Mill Pentium 4 cores, as well as the Smithfield and Presler Pentium D cores, currently use the LGA775 socket type. In July 2006, Intel released the desktop version of the Core 2 Duo (codenamed Conroe), which also uses this socket, as does the subsequent Core 2 Quad. Additionally, by the end of Q1 2007, Intel plans to release its Allendale (Core 2 Duo's equivalent of Celerons), also for LGA775. Intel changed from Socket 478 to LGA775 because the new pin type offers better power distribution to the processor, allowing the front side bus to be raised to 1066 MT/s. The 'T' in Socket T was derived from the now cancelled Tejas core, which was to replace the Prescott core.

As it is now the motherboard which has the pins, rather than the CPU, the risk of pins being bent is transferred from the CPU to the motherboard. The risk of bent pins is reduced because the pins are spring-loaded and locate onto a surface, rather than into a hole. Also, the CPU is pressed into place by a "load plate", rather than human fingers directly. The installing technician lifts the hinged "load plate", inserts the processor, closes the load plate over the top of the processor, and pushes down a locking lever. The pressure of the locking lever on the load plate clamps the processor's 775 gold contact points firmly down onto the motherboard's 775 pins, ensuring a good connection. The load plate only covers the edges of the top surface of the CPU; the centre is free to make contact with the cooling mechanism placed on top of the CPU.

[edit] Improvements in Heat Dissipation

The force from the load plate ensures that the processor is completely level, giving the CPU's upper surface optimal contact with the heat sink or cold-water block fixed onto the top of the CPU to carry away the heat generated by the CPU. This socket also introduces a new method of connecting the heat dissipation interface to the chip surface and motherboard. With Socket T, the heat dissipation interface is connected directly to the motherboard on four points, compared with the two connections of the Socket 370 and the "clamshell" four-point connection of the Socket 478. This was done to avoid the reputed danger of the heatsinks/fans of pre-built computers falling off in transit. LGA775 was announced to have better heat dissipation properties than the Socket 478 it was designed to replace; but the Prescott core CPUs (in their early incarnations) ran much hotter than the previous Northwood-core Pentium 4 CPUs, and this initially neutralized the benefits of better heat transfer. However, modern Core 2 Duo processors run at lower temperatures than the Prescott CPU's they replace.

See List of Intel Pentium 4 microprocessors

[edit] The Bent Pin Issue

For reasons explained above, that LGA775 is expected to have lower CPU replace cycles than those with pins on the CPU.^[2] While many Intel processors continue to sell for a higher price than most of the motherboards they are designed to fit into, some consumers may prefer to replace the entire motherboard rather than the CPU alone. Consumers may also notice another problem when attempting to return a motherboard for free (RMA) replacement: many manufacturers require that the returned board is sent with the original socket cover - this can be a problem, since the small plastic cover is easy to lose or accidentally throw away.

[edit] References

1. ^ New P4 Socket Type LGA775 (Socket T). asisupport.com. Retrieved on March 14, 2007.
2. ^ Socket Manufacturer Makes Socket 775 Sturdier.. X-bit labs. Retrieved on March 14, 2007.