Memory terminology questions

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toronado455

1. Does "Single Sided" = "Single Bank"?
2. Does "Double Sided" = "Dual Bank"?
3. Is a KVR333X64C25/512 module "Single Sided" or "Double Sided"?
 
toronado455 said:
1. Does "Single Sided" = "Single Bank"?
2. Does "Double Sided" = "Dual Bank"?
3. Is a KVR333X64C25/512 module "Single Sided" or "Double Sided"?
Click to expand...

If the chips are on both sides, it's double sided. THe module you gave
is double sided. (i checked)

IIRC banks is different from sides.
 
toronado455 said:
1. Does "Single Sided" = "Single Bank"?
No.

2. Does "Double Sided" = "Dual Bank"?
Click to expand...

No.

Double sided means only that there are chips on two side because they won't all fit on one side.
Each bank of memory can be individually addressed; e.g. two banks can use address interleaving to increase performance.
 
Mike Walsh said:
No.

Double sided means only that there are chips on two side because
they won't all fit on one side.
Each bank of memory can be individually addressed; e.g. two banks
can use address interleaving to increase performance.
Click to expand...

A bank consists of enough chips to make a 64 bit wide array.
(The DIMM interface has a 64 bit wide data bus.)

Eight chips having 8 data bits each makes a 64 bit wide array.
Four chips having 16 data bits each makes a 64 bit wide array.
It is pretty hard to just eyeball a module, and tell exactly
what is going on, without going into more detail.

You could stick eight chips of 16 bit width, on one side of a
module, in which case you could have two banks on the same side
of the module. Normally, a module would not be designed that
way. It is better to put a bank on each side of the module, as
the data bus stubs could be kept a bit shorter by doing so.

AFAIK, a DIMM slot has enough control signals to control two
banks. You could stick 16 chips of width 16 bits, on a module,
and that would be enough to build four banks of memory, but
then there aren't enough control signals to select a particular
bank.

This could well be a picture of four 16 bit wide memory chips,
making one bank on that side of the module.

http://www.guenstiger.de/gt-preisvergleich/EDV_PC_NoName_DDR_RAM_256MB_PC_333.htm

This example could be eight 8 bit wide memory chips, sitting on
one side of the module and making one bank.

http://www.christophlorenz.de/img/comp/ram_512mb_ddr266.jpg

Most of the time you'll find one bank per side of a module, but
if a person put their mind to it, they could also arrange two
banks to sit on one side of the module. The manufacturing advantage
of sticking two banks on one side, is only one pass through the
soldering equipment, which considering the razor thin margins
in selling memory, might be worthwhile from the manufacturer's
perspective. I don't know exactly how bad that would be
for signal quality though. I've done analog simulations of
such things in the past, and been surprised at the answers.
It is hard to guess at and be sure.

Paul
 
Paul said:
OK.
Click to expand...

My motherboard manual uses the terms "Single Sided" and "Double Sided"
to describe what type of modules can be used in which slots. Are they
talking about the module physically having chips on both sides or one
side? Or are they talking about Single Bank vs. Dual Bank? The MB has
three DIMM slots and four rows (0,1,2,3). The manual says that only a
"Single Sided" module can go into slot #3, and then ONLY if there isn't
a "Double Sided" module in slot #2 since both slot #2 and slot#3 share
the same two rows (2&3).

Here is what the manual says are the two possible configurations:

DIMM1 DIMM2 DIMM3
DS/SS DS Empty
DS/SS SS SS

DS="Double Sided"
SS="Single Sided"


Currently, both slots #1 and #2 have Kingston KVR333X64C25/512 modules
in them. I need to know if those modules are "Single Sided" or "Double
Sided". Because if they are "Single Sided" then I can move them into
slots #2 and #3 and put a new module in slot #1. But if they are
"Double Sided" I will have to pull at least one or both of them from
the system in order to upgrade.
 
toronado455 said:
My motherboard manual uses the terms "Single Sided" and "Double Sided"
to describe what type of modules can be used in which slots. Are they
talking about the module physically having chips on both sides or one
side? Or are they talking about Single Bank vs. Dual Bank? The MB has
three DIMM slots and four rows (0,1,2,3). The manual says that only a
"Single Sided" module can go into slot #3, and then ONLY if there isn't
a "Double Sided" module in slot #2 since both slot #2 and slot#3 share
the same two rows (2&3).

Here is what the manual says are the two possible configurations:

DIMM1 DIMM2 DIMM3
DS/SS DS Empty
DS/SS SS SS

DS="Double Sided"
SS="Single Sided"


Currently, both slots #1 and #2 have Kingston KVR333X64C25/512 modules
in them. I need to know if those modules are "Single Sided" or "Double
Sided". Because if they are "Single Sided" then I can move them into
slots #2 and #3 and put a new module in slot #1. But if they are
"Double Sided" I will have to pull at least one or both of them from
the system in order to upgrade.
Click to expand...

I can tell you have an 845 chipset :-)

http://www.valueram.com/datasheets/KVR333X64C25_512.pdf

Notice the chips are 8 bits wide (32MX8). There are eight
chips on one side of the module. That is a bank. There
are eight chips on the other side of the module. So the
module is "DS" for the purposes of your user manual. You
may use only two KVR333X64C25_512, placed in DIMM1 and
DIMM2. DIMM3 remains blank and unusable.

The chances of being able to use the DIMM3 slot are pretty
slim. Most readily available 512MB DDR modules are "DS", and
so you get to use two of them. If you want more memory, shop
for 1GB modules, constructed with 64Mx8 chips. Those modules
will be "DS" as well, and you can use two of them. There
will be 16 chips. The 1GB module is just a 512MB module,
where they change the chip type from 32Mx8 to 64Mx8.

There is an example of the proper type of 1GB module here:

http://www.valueram.com/datasheets/KVR333X64C25_1G.pdf

Note that there are some cheaper modules for sale. They
can use x4 chips, which is a bad choice for an unbuffered
DIMM. These are typically sold on Ebay, with no warning
as to their crappy properties. The Ebay seller won't tell
you the width of the memory chips, or how the banks are
set up. As long as you buy name brand 1GB modules and stay
away from Ebay, there is much less chance of being screwed.

Paul
 
Paul, thanks for your very infomative and helpful replies.

I've decided I'm not going to upgrade the memory in this machine right
now. I'll make do with what's on it now and I may upgrade later if the
prices come down on 1GB modules. If and when, I would use either
Kingston or Crucial, but I'd never buy RAM from eBay.
 
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