EDIT: AMD is moving to new socket in the future: AM2, which features DDR2 support (940 pins, but not Socket 940 compatable)
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deject's Guide to Desktop CPU Sockets
Intro:
These days, there are a ton of CPU Sockets to shop around for. Socket A, Socket 370, Socket 754, and what's the difference between Socket 939 and 940? WTF was AMD thinking? And what in god's name is LGA775? For the hardware newbie making a purchase descision can be frustrating and can lead to expensive mistakes, unless you have a handy guide (like this one!) to help you out.
The Guide:
In this guide, I'll be covering the most common desktop socket types from the last 5 or 6 years. I don't see the need to go over the good ol' Socket 7 at this point. The most detail will be on the current CPU sockets for mid-range and top-of-the-line motherboards. In addition, I will be giving shopper's advice on the sockets that are available today.
A. Older Sockets (pre-Athlon 64/Pentium 4)
1. Intel Sockets
I. Socket 370 (CPU support: Pentium 3/Celeron (P3 family), VIA C3 processors)
Socket 370 was Intel's move back to a socket from making slotted CPUs. Starting with the Pentium 2,
Intel decided to package their CPUs in a slotted format to make use of a PCB for more cache memory.
At the time it was a great way to boost performance, but eventually the technology allowed them to
migrate back to a CPU Socket. The Socket 370 was the mainstay for Intel boards for quite a while.
2. AMD Sockets
I. Socket A (a.k.a. Socket 462)
(CPU Support: Athlon/Duron/Athlon XP/Sempron)
Socket A will be known in history as the socket that kept the Athlon's performance edge over the Pentium 3.
When Intel moved to Socket 370, the faster cache on 370 CPUs was killing off the performance advantages of
the Athlon core. Thus AMD followed Intel's lead and went back to a socketed CPU. Unlike the Socket 370,
Socket A is still widely used and is still getting new CPUs (the Sempron), years after it's release.
B. Current Sockets (Athlon 64/Pentium 4)
1. Intel Sockets
I. Socket 423 (Pentium 4/Celeron (P4 family))
The original Pentium 4 socket, Socket 423 was released just to get the Pentium 4 out there. Debuting
at 1.5 GHz, the newfangled Pentium 4 signalled a change in Intel's strategy. Instead of having
Pentium 3-esque performance at lower clock speeds, they decided to have a somewhat weaker CPU per clock,
but crank the core to (then) unheard of speeds. AMD had beaten them to the 1 GHz mark, but Intel was
determined to regain the performance crown. Thus the Pentium 4 was born. Early adopters that bought
into the Pentium 4 enjoyed their motherboards for a year or so until Intel announced the move to Socket 478.
Everyone realized that Socket 423 was a stopgap on the way to 478, and all the eary adopters had to
buy new motherboards again. In general, I'd advise not buy a Socket 423 motherboard, especially if you're
looking to upgrade soon. The upgrarde plath for Socket 423 is very small so unless you have an old
Pentium 4 laying around, don't bother.
II. Socket 478 (Pentium 4/Celeron (P4 family))
The new Intel flagship socket for more than a couple years, Socket 478 should have been released with the
Pentium 4 at launch. The extra pins on 478 allowed the CPU to draw more power than was possible on
Socket 423. This socket supports a large variety of Pentium 4's; almost every P4 released from 2001
through mid-2004 was for the Socket 478. If you're looking for a solid mother board with a lot of CPU options
then the Socket 478 is good option.
III. LGA775 a.k.a. Socket T (Pentium 4/P4EE/Pentium D)
LGA775 is the current Intel platform for the desktop. All current and near future Pentium 4/Pentium D
CPUs will be released for LGA775. "LGA" stands for Land Grid Array, referring to the new style ball
and socket format instead of pins. Using a ball-and-socket allows for better connectivity than the old pin
format. This allows less resistance than a pin allows, reducing power consumption. I have heard of
problems installing LGA775 CPU, and that the balls are much more fragile than pins, but I can't back this
up, as I haven't personally tried installing a LGA775 CPU. If you're looking for an Intel motherboard, a
mobo based on LGA775 is definetly the way to go. These motherboards support all the new features like DDR2
and SATA. For Intel, You can't beat a LGA775 board.
2. AMD Sockets
I. Socket 754 (Athlon 64/Sempron)
Now intended for budget CPUs, the Socket 754 was the original Athlon 64 socket. Like all Athlon 64 platforms,
motherboards with Socket 754 are tied to a specific CPU and RAM type. Socket 754 only supports single channel
DDR RAM, and a slower Hypertransport interconnect. In general, there is not much point in getting such a
board unless you are budget limited and can't spring for the AMD socket of choice, 939.
II. Socket 940 (older Athlon 64-FX/Opteron)
The Socket 940 is the original home for the AMD Opteron and Athlon 64-FX lines (FYI: The Athlon 64-FX is just
an Opteron with two of the three Hypertransport interconnects disabled). CPUs based on the 940 require Registered
DDR memory. These RAM modules offer much better reliability that normal RAM, but also add a lot of latency, so
their performance is noticably lower. Since the Athlon 64-FX is meant for desktop performance, AMD moved it to
Socket 939 so it could use the faster (and cheaper) unregistered RAM. The Opterons are still using 940, since
they are aimed at the server market, where stability is paramount. Socket 940 motherboards come in single, dual,
quad, and eight processor models, but each board needs a specific Opteron type meant for multi-processor usage.
Opterons meant for dual processor rigs cannot be used in an eight processor environment. Currently, buying a
Socket 940 board only makes sense if you're building a server, or if you get a steal on an older Athlon 64-FX.
III. Socket 939 (Athlon 64/64-FX/64 x2)
Socket 939 is the best option for building an AMD based system. All new desktop Athlons for the near future
will be Socket 939 CPUs. Not surprisingly, the Socket 939 is extremely similar to the Socket 940. The only
real difference between the two is that Socket 939 does not require the same registered RAM that Socket 940 does.
The socket allows Athlon 64's/FX's/x2's dual channel RAM and Hypertransport links running at 1GHz instead of
the 800MHz ones on the Socket 754. Thanks to the nForce 4 family, AMD CPUs now have PCI-Express support,
including SLI for dual videocard goodness. Soon, AMD will add in support for DDR2 in their Athlon line. People
will have to dump their motherboards and CPUs in order to upgrade, but that is a drawback of the Athlon 64/Opteron
design, not the socket. If you want to build an AMD based PC, you'll be best served by getting a Socket 939
motherboard and CPU.
C. Future Sockets
1. Intel
LGA775 is going to be around at least through the end of 2005, and I'd predict it will be around through the first half
of 2006. Rumor is that a new socket with 480 pins will be used, but no one knows what core it will be used for.
2. AMD
Socket 1207 will be the new home of the Opteron line, but beyond that is anyone's guess. Like LGA775, Socket 939 will
stick around for quite a while, but don't expect to simply swap out CPUs and RAM when AMD decides to support the new tech.
AMD's new socket, dubbed Socket AM2 has 940 pins and features DDR2 support. AM2 will be the new home of the Athlon 64/FX
series of CPUs when it's released sometime around the summer of 2006.
The End!
Thanks for reading this! I'm planning on writing more guides soon as well as keeping this one updated.
http://www.5punk.co.uk
Wow nice piece of reporting, well researched and efficiently delivered. Looking forward to your next endeavour.
