the NF3 250gb chipset doesnt support NF4 type dual channel memory config - it has a single channel memory controller -
Its all single channel, no matter how many slots occupied
And it has further probs with dual sided mem sticks
It can work with one stick, but 2 or 3 needs a lowering of ras/cas rating from 2T to 3T and cas from 1 to 2.0 and multiple dual sided sticks will also necessitate lowering of FSB speeds to 333 or 200
It supports 2GB @ 400FSB
and 3GB @ 333FSB
However they can be run at 400 FSB by manually setting FSB and upping voltage, using exact same brands/models, using first tier mem, and lowering latencies to something that boots reliably.
If you should run accross single sided 1GB sticks, you would be home free
3 single sided 1GB sticks will run at FSB 400 at 2T command rate
I believe Apacer made single sided 1GB pc3200 but they were $220 ea.
http://www.anandtech.com/mb/showdoc.aspx?i=2198&p=7
Heres a longish blurb that explains it well:
(I only post this here because it comes up so often)
(Quote)
QUESTION:
My Chaintech ZNF3-250 motherboard runs an AMD Athlon 64 3200+ processor and 1GB of Kingston DDR 400 Value RAM in the form of two double-sided modules. If it boots that far, all of the RAM is checked and registers at start-up, but it's very unstable and makes the system freeze most of the time during the boot process. I read the motherboard's manual and discovered that only the first DIMM slot is compatible with a double-sided DDR RAM module. This is true because the computer runs properly if I use only one of the modules. If the other two DIMM slots are incompatible with the RAM I have, why is all of the RAM registered at start-up, and is there anything I can do in the way of, say, BIOS settings that will enable me to use the other module?
Answer
Double-sided DDR RAM modules have 16 memory chips (eight on each side of the module), and single-sided modules have only eight memory chips on one side of the module, or are engineered to have four memory chips on each side of the module, but run as if all of the chips are on the same side of the module.
That particular Chaintech motherboard has an nVidia nForce3-250 chipset and supports the new generation of AMD Socket 754 Athlon 64 processors. The specifications for any motherboard are provided in its user manual, which should be available as a download from its manufacturer's site. You can use the Google search box at the top of this page to locate the nearest Chaintech site.
I like the way this page enables easy access to BIOS updates, a Utility, the user manual, motherboard drivers, and a RAM memory compatibility list. It's a Flash site the pages of which will be slow to load on a dial-up connection.
According to the user manual, the first DIMM slot can support 1GB of DDR RAM in the form of a single- or double-sided module, but the second and third DIMM slots can only accept single-sided modules up to a total of 1GB between them.
It's difficult to have such large capacities of RAM running at high speeds without timing problems causing instability. This is especially the case with double-sided modules that have the memory chips on both sides of the module. The motherboards for both Intel (Pentium 4) and AMD (Athlon XP and Athlon 64) processors usually suffer from stability problems when running double-sided modules.
If you read AMD's specifications for the Athlon 64 processor, you'll discover the admission that it can't handle the timing issues involved in running more than one double-sided module at the full DDR 400 speed. According to the same specifications, it states that systems with two or more double-sided modules can only be operated at the speed of DDR 333 modules.
As usual, AMD is being rather conservative with its specifications, probably in order to avoid as many problems as possible. Some Athlon 64 motherboards will run as much good-quality double-sided memory (i.e., made by Crucial) as the board can be fitted with without any problems, and others support a maximum capacity of particular brands of DDR 400 RAM that should run without problems.
An nVidia nForce chipset of the kind found on that Chaintech motherboard has two independent 64-bit DDR RAM memory channels. The first DIMM slot uses one entire channel by itself, and the bandwidth of the other channel is shared by the two other DIMM slots. That is why Chaintech recommends that a double-sided module should only be fitted in the first DIMM slot, with single-sided modules fitted in the other two slots.
The capacity of a module is read from a small chip on it called the Serial Presence Detect (SPD), and that is why the full capacity of the two double-sided modules was registered even though both of them wouldn't allow the system to run.
Since the problem involves timing issues, perhaps a BIOS update might be able to rectify the situation. You can obtain the latest BIOS file for that motherboard here:
http://www.chaintech.com.tw/tw/eng/product_spec.asp?MPSNo=13&PISNo=266
If the link doesn't work, try the home page at
http://www.chaintech.com.tw/ or make use of the Google search box provided at the top of this page to locate the nearest Chaintech site.
Indeed, both of those modules might work if you just tweak the BIOS settings for the memory timings slightly. For example, increasing the Cas Latency setting, usually under the Chipset Features Setup in the BIOS, from 2 or 2.5 to 3 might do the trick. Moreover, it's known that some motherboards with this chipset only have the problem with one DIMM slot, so inserting the second module in the third slot might work.
Single-sided modules have eight memory chips, which can be 256Mbit or 512Mbit chips. If 256Mbit chips are used the module can only have a capacity of 256MB. 512Mbit chips, which are much more expensive, have to be used for a single-sided 512MB module. This is why a 1GB single-sided module is considerably more expensive than two 512MB single-sided modules - the very expensive 1024Mbit memory chips have to be used. Double-sided modules use the cheaper 256Mbit chips for 512MB modules, because they have 16 memory chips per module. Therefore, a 1GB double-sided module has to use the 512Mbit chips.
Using single-sided modules is the only guaranteed way to have large amounts of RAM installed and running with stability at its full speed.
http://www.pcbuyerbeware.co.uk/RAMProblems.htm