Memory Bus Widths

[hongman]

Right. Where to start??

Came off the A+ course, and now I want to claify this, but I know that even beofre I post this, it isnt going to make sense.

Ok.

Was informed that basically, if you had a 64 bit bus width (as on Pentiums?) you needed to put 64 bit's worth of memory in the banks, otherwise it would not work.

I.E 64bit bus would need 2 x 72 pin SIMMS (apparently 32bit each?) otherwise it wouldnt work...

IS that right??

If so, then what happens if you added 4 SIMMS, 72pin each? that would total 128 bits. Apparently this extra would be ignored, but does that not mean that the RAM on the sticks would also be ignored??

The tutor said we may of been getting confused with memory address and something else, alas she never bothered to explain it.

Someone I spoke to came up with a theory, that RAM operates on a stack system basis. So if we use the above example, the system would use the amount of RAM that the system recognised in the range of bits is needed (in this case the first 2 SIMMS) and then use the other 2 as 'storage', simply passing up the data into the first 2 sticks as the space on them free up...

True/False?

And here's the other bit. If Pentiums already run at 64 bit bus width, what is so special about these new AMD64's?

Also, how are the amount of pins relational to how many bits a SIMM or DIMM is?

Thanks to those who read this, if it dont make sense please let me know!!

Now my head is going to explode.

Hong

[DrMDJ]

Ok. First, shoot your tutor. Second, shoot that "someone". Third, quit this course. WOW! Just kidding!

It's way too early and I've had way too little coffee to even know where to begin reponding on this one Hong. My brain just ain't up to it yet. Definately should (hopefully) provoke some good dicussion here though. I understand what you're after, though there is some confusing and mixing of of things here for sure.

PS. And just think, you're paying to get these cronic headaches. Come to think of it, I guess so are we. Just kidding!

[hongman]

Ok. First, shoot your tutor.Third, quit this course.

If only you knew how many times I thought about doing this...

Right, SOMEBODY GET SOME COFFEE FOR THE DOC!!

Definately should (hopefully) provoke some good dicussion here though.

Me too

I understand what you're after,

I'm glad someone does

And just think, you're paying to get these cronic headaches.

Well the course is free for me, I just feel sorry for the PAYING clients...

[hongman]

Here doc (and any others)...help yourself to a virtual coffee, on me

On onto the serious stuff...

[DrMDJ]

LOL. Thanks, but with some of the questions you ask lately Hong "virtual" just won't cut it. In fact, something even stronger may be in order.

[hongman]

Hey ya all

As soon as anyone is brave enough to try and answer this one, go right ahead.

Not pushing or anything, just dont want this thread to go dead

[hongman]

So Is noone brave enough to break this to me gently?

[Train]

It is ambush time!

Now nail that instructor's feet to the floor and get a answer!
Have IT,[can not be human] correct what they did not explain.

I taught industrial hydraulics at the college level and boy, do I wish I was a fellow student.
So take your question and cram it down their throat again and agaain until they do. Then please post what they finally give you.



Have fun!
I be waiting.

[SuperSparks]

Do you have a copy of Upgrading and Repairing PC's, Hong? Because there is an excellent section on memory there, that would probably explain a lot of this more easily than any of us can here.

As far as the difference between the P4 and AMD64, the limiting factor isn't anything to do with bus width, but rather with the internal registers.

The P4, and 32-bit CPUs in general can address 2 ^ 32 bits which equals 4294967296 bits or 4Gb.

The AMD64 can address 2 ^ 64 bits = 18446744073709551616 bits or 17 billion GB!

[Sarrkazztic]

Originally posted by DrMDJ
with some of the questions you ask lately Hong "virtual" just won't cut it. In fact, something even stronger may be in order.

I have been wanting to say this for months.

[SuperSparks]

And if any of you need your coffee fix without moving from the 'puter, then this is what you need

http://articles.pimprig.com/featured...ne_machine.php

[hongman]

Thanks all.

Sparks: No, I dont have a copy of Upgrading and Repairing PC's, who is the author? I want to make sure I get the right copy. Thinking about it, I think I may have heard of thise book before.

Kazz: Have I been that bad?

Train: I will re-ask again tomorrow. Lord be with me, I shall post back if I dont get arrested!!

Thanks again.

Hong

[Train]

Scott Mueller and this is a Amazon.com link.

Snd here is the latest version of the book. Pricey, but he does a darn good job. My copy is way older version wise.

[hongman]

Thanks Train

[SuperSparks]

Yep, if you are doing A+, or just need to know about computer hardware, that book is a must have. It is a true goldmine of information.

You can get the 16th (latest) edition for around £30 from:

http://www.amazon.co.uk/exec/obidos/...604412-4086812

or:

http://www.compman.co.uk/scripts/browse.asp?ref=687758