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Desktop PC Processor Sockets: The Types of Socket Used by AMD and Intel Processors (CPUs)

Last updated on 20 January 2010

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An introduction to Intel and AMD processor sockets

The rate at which Intel and AMD change the kind of motherboard sockets (it used to be slots for a short period) that their desktop PC processors use, is confusing, as well as being infuriating, because it means that even if the form-factor remains the same (ATX or micro-ATX), every time the type of processor housing changes, or there are technical changes to the existing platforms, a new motherboard usually has to be purchased if you want to upgrade from one type of socket to another, or even use a more advanced processor that uses the same type of socket. You have no choice in the matter because the previous housing is then no longer supported.

AMD usually makes its desktop PC processor sockets last much longer than Intel. For example, the processors that run from its latest Socket AM3 processors are backwards-compatible with its predecessor, Socket AM2+, if a BIOS update for the motherboard is installed. This means that a Socket AM3 processor (e.g., a Athlon II and Phenom II) will work in a Socket AM2+ motherboard. However, a Socket AM2+ processor (cannot run on a Socket AM3 motherboard. This means that owners of a Socket AM2+ motherboard can upgrade the processor without having to change the motherboard or RAM memory.

Socket AM2+ is the successor to Socket AM2 that is used by several AMD processors such as Athlon 64 X2. Socket AM2+ is fully compatible with Socket AM2, so that processors designed for Socket AM2 run on Socket AM2+ motherboards and vice versa.

However, with Intel, a change of processor socket (say Socket LGA775 to Socket LGA1366) almost always means the user of the initial socket type having to change the motherboard, processor and even the RAM memory if a new type of memory is made available at the same time as the new processor.

In short, when Intel brings out a new range of processors, it always has a new socket type that is not backwards-compatible with its predecessor socket type or forwards-compatible with the next socket type. Moreover, later Intel processors of a socket type may require a new motherboard, because technical improvements to it make it impossible to run the latest processors of a particular socket type on earlier motherboards that use that socket type.

This makes upgrading an Intel-based desktop PC much more expensive than upgrading an AMD-based PC, especially given that AMD processors are usually cheaper than equivalent Intel processors and Intel-based motherboards are usually more expensive that AMD-based motherboards.

On this page the earliest of a range of desktop-PC Intel or AMD processors are dealt with first and the latest of a range are dealt with last, therefore you will first read about redundant or ageing processors and then read about the latest processors and their sockets. The current sockets used by AMD for its desktop processors are Socket AM2+ and Socket AM3. Intel's current sockets are Socket LGA775, Socket LGA1366 and (the latest) Socket LGA1156.

Back in 1997, Intel moved from housing its processors in Socket 7 (used in 66MHz FSB motherboards) and Super Socket 7 (SS7) sockets (used in 100MHz FSB motherboards) to using a slot (like a PCI/AGP slot), which it called Slot 1.

The Pentium 233MHz MMX processor was Intel's last SS7 processor.

It then proceeded with Slot 1 motherboards to run its Pentium II and III processors, and the cut-down economy versions (with none or less Level 2 cache), called the Celeron.

All of a sudden, the Slot 1 Celeron processors couldn't compete with the SS7 AMD K6-2 and K6-3 processors, and Intel turned the Celeron range back into socketed processors, this time using what it called Socket 370. The processor has 370 pins and the socket has the matching pin grid array to accept them.

Then Intel dropped slot processors altogether in favour of socketed processors.

Some of the Celeron and the last Pentium 3 processors use motherboards that have the Flip Chip - Pin Grid Array or FC - PGA socket. - This is not a new socket, just a new name for Socket 370.

However, Socket 370 is now dead. The Celeron and Celeron D (not a dual-core) processors do not use Socket 370 or Socket 478 motherboards, they use the same LGA775 socket as Pentium D (dual-core) and Pentium 4 processors, both of which have been superseded.

Intel Pentium 4 processors (superseded) use the earlier Socket 423 and Socket 478, or the current Socket LGA775 motherboards, which run the latest Intel Core 2 Duo (dual-core processors) and Intel Core Quad (quad-core processors).

The image below shows a Socket 478 motherboard that is no longer in production. The processor's socket is surrounded by the fitting to which the heatsink and fan unit is fitted. It is an unusual board because it only has one PCI slot (white, bottom left-hand corner).

AMD used Socket 7 motherboards (with a 66MHz FSB) for its K6 processors , and Super Socket 7 motherboards (with a 100MHz FSB) for all of its K6-2, and K6-3 processors, but followed Intel when it decided to use a slot, which it called Slot A, for its first Athlon processors.

Click here! to go directly to a table containing the specifications of AMD's superseded K6, K6-2, and K6-3 processors.

Having also moved away from slotted processors, AMD Athlon, Athlon XP, and Duron processors went on to use Socket A (aka Socket 462) motherboards that are now no longer in production, but can still be bought from outlets such as eBay.

Socket 754 and Socket 939 motherboards run AMD's Athlon 64 and Sempron desktop processors, both of which have been discontinued. AMD has migrated all of its desktop processors to the Socket AM2 and Socket AM2+ platforms. AMD's Socket AM3 triple-core and quad-core Phenom II processors and the motherboards that run them were made available in February 2009.

Socket AM2 - http://en.wikipedia.org/wiki/Socket_AM2

Socket AM2+ - http://en.wikipedia.org/wiki/Socket_AM2%2B

Socket AM3 - http://en.wikipedia.org/wiki/Socket_AM3

Socket LGA775 motherboards run Intel's Celeron (single-core), Pentium 4 (single-core), Pentium D (dual-core) and Core 2 Duo (dual-core) desktop processors. You have to make sure that a Socket LGA775 motherboard supports a Pentium D or Core 2 Duo dual-core processor, because some of the earlier Socket LGA775 motherboards cannot run the latest processors made for this socket.

Socket T (also known as Socket LGA775) -

http://en.wikipedia.org/wiki/Socket_T

Intel's Socket LGA775, Socket LGA1366 and Socket LGA1156 platforms

Visit the Processors section of this site for more information on Intel's Socket LGA775 desktop PC processors.

Note that Intel's Core i7 Socket LGA1366 quad-core desktop PC processors were made available in September 2008. More information on them is provided further down this page.

The latest Socket LGA1156 Core i5 and Core i7 quad-core desktop-PC processors were made available on September 8, 2009. More information on them is provided further down this page.

AMD's Socket AM2 and AM2+ platforms

AMD's range of Socket AM2 processors have been available for some time together with the motherboards that run them made by the major manufacturers.

In November 2007, the AMD Socket AM2+ quad-core processors called the Phenom arrived on the market. Less expensive, triple-core versions of those processors are now available.

In February 2009, AMD's Socket AM3 triple-core and quad-core Phenom II processors were made available.

AMD's Socket AM2/AM2+ processors have an onboard memory controller that supports the latest DDR2 RAM. The latest Socket AM3 platform supports DDR3 RAM memory.

Here are links to the new motherboards from Asus, MSI, and Gigabyte:

"ASUS will of course make significant use of AM2 in many different variations. Currently we offer four variations of AM2 boards: the M2N32-SLI Deluxe, M2N-SLI Deluxe, M2V and the M2NPV-VM. The first of these boards, the M2N32-SLI Deluxe, promises to set a new standard for gaming. The M2N32-SLI Deluxe supports dual graphics card operation to run the most video resource-hungry applications. The board comes equipped with an NVIDIA nForce® 590 SLI™ MCP chipset, two PCI Express x16 slots for two identical SLI-applicable graphics cards to run simultaneously in SLI (Scalable Link Interface) mode, and even an optional fan for water-cooling." - http://usa.asus.com/news_show.aspx?id=3462

MSI Socket AM2 motherboards - http://www.msi.com.tw/

Gigabyte Socket AM2 motherboards - http://www.gigabyte.com.tw/

AM2 for Power Users: Foxconn C51XEM2AA-8EKRS2H Motherboard Review -

"Foxconn proves the AM2 advantage by posting the best overall performance we’ve seen from a 2GHz Athlon64 3200+. But Foxconn’s advantage doesn’t stop there, as this is also the most fully featured board we’ve tested, offering everything from six-drive RAID arrays to dual-gigabit network teaming and net packet prioritization. Support for two graphics cards with full x16 transfers, SLI mode, x4 PCI Express add-in cards, the latest processors, and DDR2-800 makes the C51XEM2AA-8EKRS2H about as future-proof as anything else on the market." -

http://www.sysopt.com/features/mboard/article.php/3615946

AMD's Socket AM2+/AM3 platforms: The Phenom and Phenom II processors

For the first time since its take-over of the graphics-chip company, ATI, AMD has produced a complete platform, code-named Spider, that consists of the new Phenom processor, the 790FX motherboard chipset, and the Radeon HD3800 series of graphics cards.

Intel's quad-core processors are really just two dual-core processors in a single package. However, AMD's quad-core processors have all four cores in a single chip.

The good news is that the Phenom processors, and all of the Athlon 64 Socket AM2 processors, can be used on either the new Socket AM2+ motherboards or on Socket AM2 motherboards. In other words, in order to run, the Phenom processors do not require a new Socket AM2+ motherboard. They will also run in a Socket AM2 motherboard. A Phenom processor uses Hypertransport 2.0 on an AM2+ motherboard, and Hypertransport 1.0 on a AM2 board. However, a BIOS update is probably be required to run a Phenom processor on an AM2 motherboard.

The single-die, quad-core design involves a greater risk of manufacturing defects resulting in lower yields per silicone wafer. If only one of the four cores is defective, it cannot be sold as a quad-core processor. However, if one of the cores is defective, it is deactivated with the intention in mind of marketing it as a triple-core or tri-core processor. AMD’s customers will therefore soon be able to purchase a less expensive triple-core processor. Triple-core versions of both the Phenom and Phenom II processors are available.

Each of the four processor cores of a Phenom processor possesses its own 512 KB of L2 (Level 2) cache, and all of the cores have access to 2MB of L3 (Level 3) cache, which produces an increase in performance.

The Phenom II processors, which are manufactured on a 45nm fabrication process and which support DDR3 memory, will run in Socket AM2 and AM2+ motherboards. AMD's first ranges of Socket AM3 45nm Phenom II triple-core and quad-core processors were made available in February 2009.

The other advantages of the Spider platform are that it can be upgraded to use up to four graphics cards, and the platform supports the new PCI Express 2.0 graphics standard.

Motherboard manufacturers Asus, MSI, and Gigabyte were at the introduction of the Spider platform in Warsaw to show off their AM2+ motherboards. According to AMD, the MSI K9A2 Platinum (MS-7376) is currently the best of the offerings.

AMD Phenom Quad-Core Processors -

http://www.amd.com/...0,,30_118_15331_15332,00.html

AMD's Phenom II triple-core and quad-core processors are now available

February 17, 2009 - AMD has released several new Socket AM3 Phenom II triple-core and quad-core processors, including the triple-core Phenom II X3 720 Black Edition (2.8GHz) and the quad-core Phenom II X4 810 (2.6GHz). AMD has also released a lower-clocked triple-core Phenom II X3 710 (2.6GHz) and OEM-only quad-core Phenom II X4 805 (2.5GHz) and Phenom II X4 910 (2.6GHz) models. These processors are primarily designed to use a Socket AM3 platform, but are backward-compatible with existing Socket AM2+ motherboards. The Phenom II processors use DDR3 RAM memory, but can use DDR2 memory when used in a Socket AM2+ motherboard.

The web is full of interesting information on these new processors. To locate it, you can enter phenom ii in the Google search box at the top of this page (with its Web radio button enabled).

All of the specifications of AMD and Intel processors for the desktop PC

Visit the following two pages to view tables containing all of the technical specifications (socket type, clock speed, supported instruction sets, cache, etc.) and other information, such as the dates of release, of all of the processors made by AMD and Intel up to the present. The earliest processors are listed first. The further down the list a processor appears, the more recent it is. Look down the Socket/Slot column for the socket type for a particular model of processor.

Desktop CPU Comparison Guide - AMD processors -

http://www.techarp.com/showarticle.aspx?artno=337&pgno=0

Desktop CPU Comparison Guide - Intel processors -

http://www.techarp.com/showarticle.aspx?artno=337&pgno=4

Annotated images of ATX Socket LGA775, Socket A and Socket 939 motherboards

Intel's latest desktop PC processors use Socket LGA775 motherboards and AMD's desktop PC latest processors are fitted into and run from Socket AM2/AM2+/AM3 motherboards. Visit the Annotated images of ATX Socket LGA775, Socket A and Socket 939 motherboards page on this site to see annotated images of those two socket-type motherboards. Click your browser's Back button to return to this point on this page.

Note that Intel's new Core i7 Socket LGA 1366 quad-core desktop PC processors have been made available. See the next item on these processors.

Intel's Socket LGA1366 Core i7 quad core desktop-PC processors

November 18, 2008. - Intel has released three of its new Socket LGA1366 quad-core processors. Here is a good review:

Intel Core i7 - http://www.pcpro.co.uk/reviews/233892/intel-core-i7.html

And here is the information on the new processors on Intel's website:

Intel® Core™ i7 Processor -

http://www.intel.com/products/processor/corei7/...

The major motherboard manufacturers have brought out motherboards that support the new Intel desktop PC processors.

Asus - http://www.asus.com/products.aspx?l1=3&l2=179

MSI - http://global.msi.com.tw/index.php...

Gigabyte - http://www.gigabyte.com.tw/Products/Motherboard/...

User manuals are available from all three of those manufacturers, so you can download copies and have a look at what is on offer.

This is how Intel describes the processors on its website: "These processors will feature Intel® Hyper-Threading Technology, also known as simultaneous multi-threading, and are capable of handling eight software "threads" on four processor cores."

Asus, has made its P6T Deluxe motherboard with the X58 chipset, which has the new LGA1366 processor socket, available to reviewers world-wide.

The new motherboard provides new power-saving and overclocking technology. As an optional extra a device known as the OC Palm is available that provides overclocking on-the-fly during gaming or benchmarking. You can see an image of the device attached to a USB port on this page:

New ASUS P6T DELUXE with Super Hybrid Engine Delivers Maximum Overclocking and Energy Efficiency -

"The P6T DELUXE adopts the usage of TurboV—an advanced overclocking tool that utilizes a micro-controller to provide precise overclocking adjustments, and allow users to conveniently adjust the CPU ratio (multiplier)* for instant CPU upgrades for real-time performance enhancements. TurboV can also provide adjustments to the NB voltage, NB-PCIe voltage, CPU PLL voltage and DRAM voltage in 0.02V micro-intervals." -

http://www.asus.com/news_show.aspx?id=12949

To locate reviews of this motherboard enter asus p6T deluxe in the Google search box at the top of this page (with its Web radio button enabled).

Intel's Core i7: Blazing Fast, But Crippled O/C : Eight Virtual Cores Through Hyper-Threading -

"Just as Intel’s Core 2 has firmly established itself in the market, it is already being replaced by a completely new architecture. Unlike the switch from the Pentium 4 / Pentium D to the Core2—where the new CPUs worked as drop-in replacements on existing boards due to the fact that the processors were pin-compatible—Intel’s newest chip requires a completely new "ecosystem." But this transformation represents nothing less than a milestone for Intel..." -

http://www.tomshardware.co.uk/Intel-Core-i7-Nehalem,review-31404.html

Editor's Corner: Overclocking Core i7 -

http://www.tomshardware.co.uk/overclocking-core-i7,review-31406.html

Core i7: 4-Way CrossFire, 3-way SLI, Paradise? : Tempered Expectations -

"For the first time ever, gamers are being treated to a reasonably priced platform enabling the best that AMD and Nvidia have to offer." -

http://www.tomshardware.co.uk/core-i7-gaming,review-31407.html

Intel Core i7 (Nehalem): Architecture By AMD? -

Intel's new Socket LGA1336 processors. -

http://www.tomshardware.co.uk/Intel-i7-nehalem,review-31375.html

Intel's latest Socket LGA1156 Core i5 and Core i7 desktop-PC processors

Intel releases its Core i7 and new Core i5 processors on its Socket 1156 platform

September 8, 2009. - Intel has released three new quad-core desktop-PC processors - the first Core i5 processor (Core i5-750) and two Core i7 processors (Core i7-860 and Core i7-870), all of which use new Socket LGA1156 platform, manufactured using the latest 45-nanometer (45nm) fabrication process. The new Core i7 processors feature Intel’s HyperThreading technology, which effectively allows them to function as eight-core processors, but the Core i5 processor can only function as a non-enhanced quad-core processor. No Extreme Editions of these processors are available, so overclockers are not able to tweak the processors' frequency multipliers; overclocking can only be achieved by increasing the system-bus speed.

As with the previous Socket 1366 Core i7 quad-core processors the new Intel processors have on-chip memory and PCI bus controllers and 8MB of shared Level 3 cache. However, instead of being able to run RAM memory in triple-channel and dual-channel modes as the original Socket 1366 Core i7 processors do, the new processors can only run in dual-channel mode, which means that the motherboards that run them only have to have four memory slots for two sets of identical memory modules running in dual-channel mode, not six memory slots in order to run two sets of three identical memory modules in triple-channel mode.

Because of technological improvements, such as an improved Turbo Mode that adjusts the processor clock speed to boost single-threaded applications when other cores not being used, the new processors have similar performance to the original Core i7 processors, but are being sold at significantly lower prices (£140, excluding VAT, for the Core i5-750 compared to £180, excluding VAT, for the original Socket 1366 Core i7-920). Socket LGA1156 motherboards are also cheaper than Socket LGA1366 motherboards (many are available for below £100). However, since the new processors have a new socket, they cannot be installed in the original Core i7 processors' Socket LGA1366 motherboards. This is a negative feature considering that all of AMD's Phenom II Socket AM3 processors can be installed in the earlier Socket AM2+ motherboards.

Here are reviews of each of the three processors:

Intel Core i5-750 -

http://www.pcpro.co.uk/reviews/processors/351385/intel-core-i5-750

Intel Core i7-860 -

http://www.pcpro.co.uk/reviews/processors/351388/intel-core-i7-860

Intel Core i7-870 -

http://www.pcpro.co.uk/reviews/processors/351391/intel-core-i7-870

Intel Core i5 And Core i7: Intel’s Mainstream Magnum Opus -

"We set off testing Intel's Lynnfield processors with low expectations, but were surprised to find the new LGA 1156-based CPUs are capable of holding their own and then some. Read on for more about Turbo Boost, Hyper-Threading, P55, and our recommendation." -

http://www.tomshardware.co.uk/intel-core-i5,review-31674.html

Extreme P55: Four LGA 1156 Motherboards Over $250 [20/01/2010] -

http://www.tomshardware.com/reviews/lga-1156-p55,2519.html

The safest way to upgrade RAM memory: Use the UK and US Crucial Memory Advisors

Paul Mullen, who was the highly-respected computer guru of the Helpfile at ComputerShopper.co.uk - "I have recently been buying my memory only from Crucial Technology. I would rather pay the extra cost than waste time trying to track down the obscure program faults that bad memory can cause."

The best way to choose RAM memory for a brand-name desktop or laptop computer, or memory for a paricular make/model of PC motherboard is to make use of the Crucial Memory Advisors (provided under the brief guideline on the minimum memory requirements for Windws XP, Windows Vista and Windows 7). If the Crucial memory you receive does not work, you are guaranteed a refund and standard shipping is free.

The memory requirements of the versions of Windows Vista and Windows 7

Most of the versions of Windows Vista require more RAM memory to run optimally on a computer that doesn't use memory-hungry applications than Windows XP. A video-editing application is an example of memory-intensive software. Only Windows Vista Home Basic has a recommended minimum amount of memory of 512MB, which is the same amount recommended for Windows XP. Windows Vista Home Premium, the most popular version, and Windows Vista Ultimate require a recommended minimum of 1GB (1024MB) of memory, which is twice the amount of minimum memory recommended to run Windows XP. Note that if you are using a 64-bit version of Windows, up to 4.0GB, it requires twice the amount of memory as a 32-bit version, which can only use a maximum of about 3.5GB. For more information on computer memory, read the RAM pages of this site, which includes information on the lower memory requirements of Windows 7.

How to Use the Crucial Memory Advisor

For example, if your computer has an Asus motherboard, open the menu, scroll down to ASUS, and click GO. If, say, you have a Dell computer, scroll down to DELL, and do likewise. You will be taken to the relevant information on Crucial's website.

If you don't know the make and model of the motherboard installed in your computer, here is a good free utility - Belarc Advisor - that creates an analysis of the hardware and software on a personal computer. Look under FREE DOWNLOAD - http://www.belarc.com/. Another utility that also provides detailed information on the memory itself is CPU-Z.

Intel has a confusing numbering system for its processors

Intel has decided to use a confusing numbering system for its processors instead of using just the name of the processor and its clock-speed in gigahertz (GHz).

Learn About Intel Processor Numbers -

http://www.intel.com/products/processor_number/index.htm

The history of the PC processor from the first AMD and Intel processors up to the present models

Visit the following two pages to view tables of all of the processors made by AMD and Intel up to the present.

Desktop CPU Comparison Guide Rev. 1.2! - AMD processors -

http://www.techarp.com/showarticle.aspx?artno=337&pgno=0

Desktop CPU Comparison Guide Rev. 1.2! - Intel processors -

http://www.techarp.com/showarticle.aspx?artno=337&pgno=4

If you want are more detailed history of Intel and AMD processors from the first processors up to 2006, visit this article:

See the Processors pages on this site for more information on these processors.

Google searches

If you can't find the information you're looking for on that page, there is a mass of information on processors on the Internet. Using the Google search box at the top of this page (with the Web radio button selected) to search for phrases such as: intel + processors or amd + processors, Intel processors or AMD processors, etc., will bring up so many sites that you could probably spend a whole day visiting them.

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