Asus A7N8X-E Dual Channel plus one

By robertdor
Mar 13, 2005
  1. I have an Asus A7N8X-E Deluxe motherboard with an AMD XP 3200 Barton CPU. The mobo uses the nVidia nForce2 SPP chip set. The mobo has three memory slots. I have a pair of Corsair Value Select Dual Channel 512 sticks in the blue slots and the system works fine.

    I purchased a single stick of Corsair VS 512k to put in the third slot. When I do, the system becomes unstable. I ran a series of tests using MemTest+ to isolate the problem. All the sticks test fine when installed solo. The Dual Channel sticks are fine when they are the only ones installed. But when I add the third stick, errors and lots of them. I tried all sort of variations in slot placement and combinations of sticks. No luck.

    I researched the problem and came across a couple threads that indicates the nVidia chipset prefers the third stick to be the sum of the dual channel sticks. In other words, I could install a 1GB stick in the third DDR slot and my system might be happy.

    Before I purchase a 1GB stick, I wanted to see if anyone else has any experience with this situation.

    Another issue: Corsair only list a C3 1GB stick on their web site. The Dual Channel memory I currently use does not have the C3 on the part numbers. I can't find a non C3 1 GB stick anywhere online. Will the C3 stick work with my current memory?

    My memory settings are: 2.5-3-3-8. Voltage is 2.6. Mobo BIOS is the latest (1013). nVidia chipset and graphics drivers are all the latest.

    I create motion graphics and I need all the memory I can muster for previews and rendering. So anyway to squeeze more memory from this mobo would be a boon.

    Thanks for any help.
  2. satchmo

    satchmo TS Rookie Posts: 83

    Single Channel

    When you put both of your memories in the blue slots, you effectively turned the system into single channel mode. To enable dual channel, you must place one stick on the blue slot and one in the black one.

    Try this solution: Pull out one of the existing 512 MB stick from the blue slot and put it in the black slot. And put the new stick in the blue slot. I have the exact same processor and mobo as you, but I only have two 512 MB sticks so far. And one of them is in the blue slot, the other one is in the black. My BIOS reports dual channel memory!

    Let me know how it goes.
  3. robertdor

    robertdor TS Rookie Topic Starter

    Strange - mine says dual channel

    Very odd. My BIOS reports dual channel when I have both sticks in the blue slots. And that is what the documentation explains is the configuration for dual channel use.

    I've tried all the possible combinations of three sticks in the three slots and no matter the configuration, the three sticks will not work together. The only config where MemTest reports zero errors is when the two dual channel sticks are in the blue slots.

    At this point, I don't care if I get dual channel or not. My understanding is the performance increase is 3-5%. I need more physical memory and will sacrifice the small performance gain.

    I'm wondering if I can add a 1G stick as the third memory. Somewhere I read that the nVidia chipset likes the third memory to be the sum of the two dual channel memory sticks but I have not been able to confirm this.

    Thanks for the reply and if you have any other ideas, let me know.
  4. satchmo

    satchmo TS Rookie Posts: 83


    Sorry my suggestion didn't help. The strange thing is that when I was reading the mobo manual for the same motherboard, it clearly said to insert one stick in the blue slot and one in the black one to enable dual channel. Maybe there are differences in mobo after all, even when they seemingly have the same model.
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