Nvidia NForce 680i SL TI Mobo stops at 3GB

[Tefte]

I recently purchase 2 x CM2x1024-6400C5DHX (exact match of my existing 2GB RAM) for my NForce 680i SL TI MoBo. I have confirmed all RAM and all slots are good. I can run any combination of 3 slots and 3 sticks with no issues. Things run much quicker with 3 than with 2 as expected. However, as soon as I add my 4th 1GB stick, my machine will not even boot. Power goes on and I can hear the wheels spinning but the monitor never shows anything and the tell-tale grind of my "old floppy drive" checking for a boot disc never occurs.

 

I have searched the forums a bit (I'm still rather new) using the search tool to no avail looking for the same exact issue. While many are similar I can't seem to find this exact issue. I am hoping you'll be able to help me know if I can ever use my 4th 1GB stick of RAM.

 

Thanks!!

[RJLeong65]

I recently purchase 2 x CM2x1024-6400C5DHX (exact match of my existing 2GB RAM) for my NForce 680i SL TI MoBo. I have confirmed all RAM and all slots are good. I can run any combination of 3 slots and 3 sticks with no issues. Things run much quicker with 3 than with 2 as expected. However, as soon as I add my 4th 1GB stick, my machine will not even boot. Power goes on and I can hear the wheels spinning but the monitor never shows anything and the tell-tale grind of my "old floppy drive" checking for a boot disc never occurs.

 

I have searched the forums a bit (I'm still rather new) using the search tool to no avail looking for the same exact issue. While many are similar I can't seem to find this exact issue. I am hoping you'll be able to help me know if I can ever use my 4th 1GB stick of RAM.

 

Thanks!!

 

Try manually lowering the memory speed to DDR2-667 speed with only two modules installed, and then try restarting your system again with all four modules installed. Some memory controllers don't like running all four modules at the full DDR2-800 speed.

 

In addition, check the revision (version) numbers of your two pairs of RAM. Some memory controllers will hiccup if even one of the sticks is even slightly different. And if you purchased those modules individually (one stick per package) rather than a matched dual-channel kit, you might end up with one stick that's of a completely different revision than the other three. As a result, Corsair now no longer sells its XMS2 or XMS3 series modules individually since no current full-sized desktop system uses a single-channel-only memory controller any more - they are now available only in kits of two, three, four or six sticks (the correct one to choose depends on whether your system's memory controller is dual-channel or triple-channel).

 

A third possibility if your system seems faster with 3GB than with 2GB even when only running a word processor is that your system's memory controller with only 2GB installed might have been forced to run in single-channel-only mode due to the placement of your two sticks. (For example, you might have placed your memory sticks into DIMM slots 0 and 1 instead of the correct DIMM slots 0 and 2 - and placing the memory modules into the two slots located closest to the processor and next to one another will force single-channel-only memory controller mode on most motherboards.) Remember, to run in dual-channel mode you need to place your two memory modules into exactly the two specified slots. Any other combination of two memory slots will result in either a forced single-channel-only mode or a refusal to POST.

 

These are the exact reasons why I don't recommend 4 x 1GB modules for 4GB of total RAM. It's better to replace all four of those 1GB modules with one TWIN2X4096-6400C5DHX kit (2 x 2GB modules).

[Tefte]

Awesome! Thanks for your reply!! I'll give your advice a shot in some form or another in the very near future. Since I already have the new Memory, I may upgrade one of my other PCs to 2GB, keep my other 2GB for spares and get the 4 (or 8) in one pair.

 

FYI, I did verify the memory is exactly what I ordered originally, but did not check the version - I'll likely check that also.

 

Thanks again for taking the time to reply!!