Dual Memory Question

[Tarkus]

I have a Leadtek WinFast K7NCR18G Motherboard.
Main Memory
Supports 3, 184 -pin DIMM sockets for DDR -SDRAM module
Support up to 3GB of memory
Support up to DDR 400 memory
128 bit DualDDR Memory Architecture (2 pieces memory required)

Currently there are 2, 256mb sticks and I want to upgrade to 1gb. Do I
have to "can" the 256's and buy a set of 512's? Why have 3 slots if 2
pieces of memory are required? Thanks.

 

[John]

I have a Leadtek WinFast K7NCR18G Motherboard.
Main Memory
Supports 3, 184 -pin DIMM sockets for DDR -SDRAM module
Support up to 3GB of memory
Support up to DDR 400 memory
128 bit DualDDR Memory Architecture (2 pieces memory required)

Currently there are 2, 256mb sticks and I want to upgrade to 1gb. Do I
have to "can" the 256's and buy a set of 512's? Why have 3 slots if 2
pieces of memory are required? Thanks.

I never tackled all the weird buzz on that topic to see what was true
or not but heres a thread on it that says you can

http://www.nforcershq.com/forum/nf7-s-doesnt-like-3-dimms-vt60002.html


It seems to depend on the motherboard. And there are mem compatiblity
issues. I had a bunch of them a little while ago when I tried to add
some mem to my AMD 64 939 system and so did other who bought a 754
socket AMD 3200 64 system which I also bought.

The usual buzz back then was you could only use two sticks to get dual
mem and some say thats true and point to stuff in a manual on some
boards. Others say you can have 3 sticks in fact they use 2x256 on one
channel and a 512 stick and claim to still get dual channel.

Everyone points out DC only gets you little boost, and that getting
more memory is better than trying to stick with DC if thats a choice.

You might to ask at nforcershq in the Leadtek forum sub.

By the way I bought a refurb leadtek that seemed fine and a year later
that thing was a bad cap mess. I searched and there apparently were
lots of LT boards with bad caps. One guy was whining about talking the
company where he worked into switching to nforce2 boards Leadteks it
happend to be , and 4-6 months later 3 of them started flaking out and
died making him look like an idiot. LT was a hassle to deal with but
they did give a replacement board to their credit eventhough it was
slightly past the 1 year warranty and didnt even ask for proof of
purchase date probably because they were flooded with bad cap boards.
In fact I think that was the board I bought a model just like yours.

 

[DaveW]

Yes, you have to buy a MATCHED pair of 512's.

DaveW

 

[kony]

Yes, you have to buy a MATCHED pair of 512's.

Not at all, it is not technically required, there is no
support for the assertion that it is, and it is also
repeatedly demonstrable that it is not necessary.

 

[Mike Walsh]

You can use all three slots as normal DDR memory, i.e. without the dual memory feature. The dual memory feature is dubious at best. Many times there is no performance improvement with it enabled. It does not work properly unless the memory and chipset are compatible, which is often not the case.

 

[kony]

You can use all three slots as normal DDR memory, i.e. without the dual memory feature. The dual memory feature is dubious at best. Many times there is no performance improvement with it enabled. It does not work properly unless the memory and chipset are compatible, which is often not the case.

Untrue, there is no such thing as "compatible" in this
context.

The chipset was obviously, already compatible as the board
supports it. There is no "wrong" memory choice that could
run in single channel mode but not dual channel, BUT, if the
memory bus were barely stable in single channel mode, it
could be just as instable or a little moreso in dual mode.

One does not have to choose single-channel mode to use all
three slots, nor do they have to have modules of the same
chips, same SPD programmings, or even the same size!

For example, unless the bios is buggy, on nForce2 you can
run the following:

Slot 1 - 1GB CAS3
Slot 2 - 256MB CAS2.5
slot 3 - 512MB CAS2

It would be necessary for the bios to work properly to set
CAS3 as it is the highest common timing. If slot 1 and 2
are same channel, you would have 512MB per channel for dual
channel mode and the slower single-channel access for the
remaining 768MB.

Another example-
I have an nForce2 board that scored the following in Sisoft
Sandra 2005 Memory Bandwidth Benchmark
(example is for the purposes of relative comparison only,
not maximal value because the CPU in that system only uses
133MHz FSB & 133MHz memory bus) These were not "matched" or
otherwise identical modules, just three different, random
budget-grade modules I'd picked up nearly free after rebate
a long time ago. No bios settings chanages, memory bus
locked at 100% of FSB, 133MHz and 2.5,3,3,9 timings, not
"auto". Tests ran 4 times, 1st & 2nd score were always
lower and discarded, 3rd & 4th scores averaged (were already
very close).

2 x 256MB modules in dual channel mode = 2032/1948

2 x 256MB modules in single channel mode = 1948/1841

3 x 256MB modules in mixed dual/single mode
(set to use dual channel but above 2 x 256MB
pair it operates in single channel mode) = 2030/1948


We can see from above scores that mixed memory, even with
different amounts per channel, still operated in dual
channel mode. Sandra does not test above 384MB so there was
never a time it operated outside of dual channel mode in the
3rd test.