N68-S UCC won't boot with RAM in the 2nd DIMM slot

I have a N68-S UCC motherboard from AsRock and two Patriot Pc 6400 2gb memory modules. The processor is an AMD Phenom II x2 3.2 ghz Calisto.

The computer boots fine with one 2gb stick in DIMM slot 1. It doesn't matter which of the two memory modules I use so long as they're in the first slot.

If I try to boot the system with both of the modules in, the fans start, but the computer does not post.

Same happens if I try one stick in slot 2... but I'd expect that on a dual channel set up.

disabled Cool N Quiet with no effect... system runs fine on the single 2gb stick, no-go on 4gb (2x2GB)

Is the motherboard bad? Or am I missing something in the BIOS...
2 answers Last reply
More about boot dimm slot
  1. It looks like you have a bad board a single module should work in the second slot. You could try adjusting the command rate though and set it to 2T (looking at your manual I think they call it MA timing) and then try it again.
  2. Looks like I in fact have odd memory. As it turns out the Patriot PSD22G80026 2GB memory module is rated at 800 Mhz when run in single channel, it has to be dropped to 667 Mhz when run in dual channel.
    The board will try to run it at 800 Mhz and of course it will fail to boot. You have to manually set the one stick in Bios as 667 speed memory, THEN install the other module.

    I learned all of this after I of course had RMA'd the board for the 2nd time (first one was legitimate DOA)

    Guess that's what I get for sorting by "Lowest Price" on Newegg... but it was a budget system build.
Ask a new question

Read More