Why the cpu Pin change? (Pin Grid Array)

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eddy05

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Why Pins?

If this question is lame, forgive me, but can I ask:

Why when intel upgrade their CPU's, they change the number of pins? As in Celeron/PIII 370, P4 423/478, Xeon 603... What good does increasing the number of pins do? If changing the number of pins is good, why AMD still uses Socket A 462 for their CPU's now?

I thought of this question when I looked at my Socket423 and sighed... (The only upgrading option is a 2.0ghz...)
 
From waterwheel.com :
-Address Bus, this is as the names suggest. The address bus is a set of wires that allow bits of information with memory addresses for the CPU. This give's the CPU access to information in system memory and the CPU will know where to get it. The bigger the BUS the better, much like the Data Bus. Most processors will want to dedicate more pins of the CPU for the Data BUS rather than Addressing. We want all that data we can get!

Basically the more pins they put on the CPU the more memory that it can address. A CPU with 32 address pins/lines can address 232bytes/4gbs of memory.

From P4 Comparison chart:
Pentium® 4 Processors
Comparison Chart
This chart compares the Pentium® 4 processors in the 423-pin package with Pentium 4 processors in the 478-pin package.

The features and performance of the Pentium 4 processors built using the 0.18m process are the same for both packages. They support Intel® NetBurst™ micro-architecture including hyper-pipelined technology, a 400 MHz system bus, and Streaming SIMD extensions 2 (SSE2). They are both built using the 0.18 micron manufacturing process and include 256K L2 integrated cache. The Pentium 4 processor with 512 KB cache on 0.13 micron is available in the 478-pin package and includes twice as much L2 cache.

The reason behind the pin package change is to electrically accommodate future Pentium 4 processors. Customers looking to upgrade their systems beyond 2 GHz should strongly consider purchasing a system that supports the 478-pin package.

Mostly its to widen the databus (currently 64bit) to allow more data to be dealt with per clock cycle, or widen the address bus to allow the CPU to access more memory (needs to address both RAM and HD).
 
Also as a side bar to the pin question is why did Intel then AMD go with the slot concept only to abandon it and go right back to the socket ?

When Intel moved to P-2 die size was too large to fit in a resonable size CPU socket, so they developed the slot. Slot 1 for Intel and Slot A for Athlon. Both actually identical, you could plug either into both, however the slot A was wired differently to accept the Athlon.

As time past and die size shrunk, both AMD and Intel moved back to sockets as Cartridge type CPU's where more expensive to manufacture.

In case you wanted to know. ;)
 
Originally posted by boeingfixer


When Intel moved to P-2 die size was too large to fit in a resonable size CPU socket, so they developed the slot. Slot 1 for Intel and Slot A for Athlon. Both actually identical, you could plug either into both, however the slot A was wired differently to accept the Athlon.

Its a shame that that design was abandoned. In constrast to the fragile and easily broken chips of today, those things were built like little tanks. I can't see how you would break one of those in a hurry.....

I had the slot based Athlon at home and still have a slot based Pentium III at work. Tough little things.....
 
Wow that's a lot of info! Thanks...

Can I ask another Question? Both PII and PIII has go slot CPU right? I've my PII 400mhz CPU... Can I upgrade it to any PIII? (Or even a slot Athlon?)
 
This really depends on the mobo your using. One of my roomates has a Celeron 700, but can only upgrade to a PIII 900.

It's kind of dependant on the mobo manufacturer to whether you'll be able to upgrade to a PIII or not. And as for using a slot Athlon it is more than likely impossible, as boeingfixer said, an Athlon is wired differently than the Pentium.

If you would be so kind as to post your system specs it would help alot in determining if you can upgrade or not. Best bet is to go to your manufactorers website and look around.
 
Originally posted by eddy05
If changing the number of pins is good
well, it is sorta lame, if not simplistic, to say that. It's not a matter of adding additional "pins" for the sake of having more pins, to make it better. Home and small-office buyers are much the same, regularly buying a Dell or Compaq w/ little thinking of what's actually inside

There is a difference in *ntel's and AMD's cpu architecture.
AMD was 1st to realize (or *ntel didn't care) that the slot (A) was a dead end. Intel followed. Since then, Intel has changed processor form factors every chance it gets. As preforementioned, die size etc. determine the size of the chip.

AMD has stuck with the same format since the introduction of the second-generation Athlon (T-bird) Athlon, Duron, MP, & XP all use Socket A. Think of the motherboard considerations or at least the suppliers that scramble to clear inventories each time Intel decides to add a few new pins, creating obsolescence & orphaned architectures.

We "build your own" PC enthusiasts don't like finding ourselves on a dead-end street when it comes to future upgrades. But AMD's Hammer series w/ 64 bit x86 architecture will require a larger pin grid array. along w/ other improvements.
 
THANK YOU UNCLEEL !!! I tried to tell that to someone in a post, that *ntel changes like the weather on form factors and was blasted. But it is true. AMD has only gone with TWO form factors gentlemen, Slot A and Socket A. Yes it is true that ALL socket A CPU's won't work in all boards BUT, if you buy a board now, most will support from 500 to 2100+. Can you buy an *ntel board and have that much spread ?? Go back to the P-3, which came in both slot and socket, so did Athlon. But if you go back to the original P-60 days, how many times has *ntel changed sockets ?? Off the top of my head I can count a dozen. If you go to AMD, I can count 4. AMD it seams to me uses better street smarts or thinks more of the consumer than *ntel.

I agree with you too Phantasm, those where tough little (or Big) CPU's, I actually had a friend bring me someones computer to work on that was freaking out. The person who built it didn't install any of those clips or the heatsink, he just TIE WRAPED it all together and then down the holes thru the motherboard. The CPU was literally just flopping around in the slot. It was quite funny to say the least!!!
 
HaHa! Same! I was very frsustrated by the way Intel always change its number of pins, and was wondering why AMD could stay constant for so long. When I bought my CPU/Mobo, Socket478 just came out. It kinda freak me out (I really scream) when I heard that Socket423 producing is stopped. Curses! I was looking forward to an upgrade and I -_-U, same case for my RDRAM, don't know when will it cease to exist...
 
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