Dumb thing and mixing PC2100 and PC2700 DDR RAM [long]

"John Jordan" wrote in message
...
In article , David W.E. Roberts
writes

So is it possible to mix the memory chips?

Yes, at least theoretically. Sometimes boards get confused. I had a
440BX board that refused to work with PC100 and PC133 together.

If so will the first 256Mb be faster than the 2nd 256Mb (assuming that I
put
the faster memory in Slot 0)?

No. All the memory will run at the same speed and timings.

Or will the whole bus drop to 133MHz because of the slower memory?
[That should have read 100Mhz :-( ]
That's what it's supposed to do, yes.

with thanks to ~misfit~ on alt.comp.hardware (see thread *** below. Note
that as this is cut&paste the '' are missing)

AFAICS my processor is a 2.6 GHZ Celeron.
At least, Belarc Advisor claims 2.60 (not 2.66 or similar)
So it ?should? have PC2100 because the FSB is 100MHz
It was shipped with PC2700 which will run at 133MHz but in this
configuration is only running at 100MHz
So in theory PC2100 and PC2700 should be O.K. together because they will be
running at the same speed.

Remaining question is then "Why does it have over spec memory?"
Do they just slam the same memory into all the boxes as a bulk buy?
I suppose if they all perform the same it doesn't really matter.

Belarc:
Processor
2.60 gigahertz Intel Celeron
8 kilobyte primary memory cache
128 kilobyte secondary memory cache

Main Circuit Board
Board: ASUSTeK Computer INC. P4GV-FSC REV 1.xx
Bus Clock: 100 megahertz
BIOS: Award Software, Inc. ASUS P4GV-FSC ACPI BIOS Revision 1015 12/25/2003

****************** cut&paste thread ***********************

" can I mix PC2100 and PC2700 memory?

On that system? Yes.

Looking at
http://www.crucial.com/uk/kb/answer.asp?qid=4031
the FSB speeds are
133MHz for PC2100 (doubled to 266)
166MHz for PC2700 (doubled to 333)

So what is the correct FSB speed for a 2.6GHz Intel Celeron?
And why does the ASUS manual talk about 400MHZ and 533 MHz FSB?
The further I dig, the deeper I sink!

The correct FSB for a 2.6Ghz is 100Mhz, 'quad-pumped' (Yuk! market-speak)
and called 400Mhz. Confusing huh? The "533Mhz" they talk about is actually
133Mhz 'quad-pumped'.

AMD double the true Mhz figure (DDR = Dual-Data rate) as the memory can send
a signal on both the rising and falling signal of the FSB. Intel quadruple
the actual FSB speed when the talk about memory as they have 'quad-pumped'
memory busses.

Help!
Dave R

P.S. Presumably the best thing to do is return the PC2100 and swap for
PC2700?

It's up to you, PC2700 is more flexible if you upgrade later or overclock. I
wouldn't buy PC2100 RAM and haven't for ages. PC3200 minimum, it'll run
slower if the bus is set slower no problems and gives you room for upgrading
if you need faster RAM later. Not much price difference either.

Faster memory as long as the CPU and Motherboard can utilise this.

The CPU and mobo will only run it as fast as it's set to, in your case
100Mhz standard. There is actually no advantage in having faster RAM than
the PC2100 that you have, other than the fact that you can run it faster
later if you want to. If you can swap it then I would in your shoes, get
PC2700, the same as the other stick. At least then it's rated up to 166Mhz
in case you want to use it in a faster system."

************************************************** *************

Thanks again to everyone

Cheers
Dave R

David W.E. Roberts wrote:
"John Jordan" wrote in message
...
In article , David W.E. Roberts
writes

So is it possible to mix the memory chips?

Yes, at least theoretically. Sometimes boards get confused. I had a
440BX board that refused to work with PC100 and PC133 together.

If so will the first 256Mb be faster than the 2nd 256Mb (assuming
that I put the faster memory in Slot 0)?

No. All the memory will run at the same speed and timings.

Or will the whole bus drop to 133MHz because of the slower memory?
[That should have read 100Mhz :-( ]
That's what it's supposed to do, yes.

with thanks to ~misfit~ on alt.comp.hardware (see thread *** below.
Note that as this is cut&paste the '' are missing)

AFAICS my processor is a 2.6 GHZ Celeron.
At least, Belarc Advisor claims 2.60 (not 2.66 or similar)
So it ?should? have PC2100 because the FSB is 100MHz

It really doesn't matter what the memory is rated at. PC1600 is actuallty
rated for 100Mhz, PC2100 is for 133Mhz. These are maximum ratings only.

It was shipped with PC2700 which will run at 133MHz but in this

PC2700 is specc'ed for 166Mhz FSB. (And PC3200 for 200Mhz)

configuration is only running at 100MHz
So in theory PC2100 and PC2700 should be O.K. together because they
will be running at the same speed.

Yep.

Remaining question is then "Why does it have over spec memory?"

Because I don't think any of the major memory manufacturers are producing
the slower memory anymore. None of my prefered retailers even sell PC2700
anymore. I asked one why and they said because they could get PC3200 from
the same manufacturer at the same price. Why carry stock of both? PC3200
will run at any speed up to 200Mhz.

Do they just slam the same memory into all the boxes as a bulk buy?

It makes sense. It all pretty much costs the same.

I suppose if they all perform the same it doesn't really matter.

You got it. It performs to what it's set to in the BIOS. (Up to it's max
rating of course)

Have fun!!
--
~misfit~

Belarc:
Processor
2.60 gigahertz Intel Celeron
8 kilobyte primary memory cache
128 kilobyte secondary memory cache

Main Circuit Board
Board: ASUSTeK Computer INC. P4GV-FSC REV 1.xx
Bus Clock: 100 megahertz
BIOS: Award Software, Inc. ASUS P4GV-FSC ACPI BIOS Revision 1015
12/25/2003

****************** cut&paste thread ***********************

" can I mix PC2100 and PC2700 memory?

On that system? Yes.

Looking at
http://www.crucial.com/uk/kb/answer.asp?qid=4031
the FSB speeds are
133MHz for PC2100 (doubled to 266)
166MHz for PC2700 (doubled to 333)

So what is the correct FSB speed for a 2.6GHz Intel Celeron?
And why does the ASUS manual talk about 400MHZ and 533 MHz FSB?
The further I dig, the deeper I sink!

The correct FSB for a 2.6Ghz is 100Mhz, 'quad-pumped' (Yuk!
market-speak) and called 400Mhz. Confusing huh? The "533Mhz" they
talk about is actually 133Mhz 'quad-pumped'.

AMD double the true Mhz figure (DDR = Dual-Data rate) as the memory
can send a signal on both the rising and falling signal of the FSB.
Intel quadruple the actual FSB speed when the talk about memory as
they have 'quad-pumped' memory busses.

Help!
Dave R

P.S. Presumably the best thing to do is return the PC2100 and swap
for PC2700?

It's up to you, PC2700 is more flexible if you upgrade later or
overclock. I wouldn't buy PC2100 RAM and haven't for ages. PC3200
minimum, it'll run slower if the bus is set slower no problems and
gives you room for upgrading if you need faster RAM later. Not much
price difference either.

Faster memory as long as the CPU and Motherboard can utilise this.

The CPU and mobo will only run it as fast as it's set to, in your case
100Mhz standard. There is actually no advantage in having faster RAM
than the PC2100 that you have, other than the fact that you can run
it faster later if you want to. If you can swap it then I would in
your shoes, get PC2700, the same as the other stick. At least then
it's rated up to 166Mhz in case you want to use it in a faster
system."

************************************************** *************

Thanks again to everyone

Cheers
Dave R