Member Avatar for joshhighley

I have a new Asus A7VT Terminator barebones system and 2 identical sticks of TwinMOS 128MB PC2700 DDR-DIMM. The CPU is an AMD Sempron 2400+.

The PC will POST fine with 1 DIMM installed. It doesn't matter which DIMM or socket used. The Award BIOS recognizes it as DDR333 and the BIOS will automatically set the DRAM frequency to 166MHz. If I install a second DIMM, though, the PC will not POST. I've tried manually setting all the timings to safe values and tried the BIOS's preset "Safe" timing options. The only way I can get it to POST with the 2 TwinMOS DIMMS is to manually set the DRAM freqency to 133MHz.

I tried the 2 TwinMOS DIMMs in another PC and it worked fine at 166MHz. I tried 2 sticks of Buffalo PC3200 256MB DIMMs with the Asus and it worked fine. It seems to be something with 2 TwinMOS DIMMs and the Asus MB.

Asus support hasn't called me back as promised after all their techs were busy.

Any suggestions?

Thanks,

Josh

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This kind of failure (system boots with one DIMM but not with two) usually points to a compatibility or signal‑integrity problem rather than a dead CPU or totally faulty RAM. As noted, incompatibility is a likely culprit, but a few focused checks will usually identify whether the issue can be fixed or if the modules should be returned.

Quick troubleshooting checklist:

  1. Update the motherboard BIOS to the latest official release before further testing.
  2. Confirm the required DIMM population order for dual-channel and test each stick in every slot to rule out a bad socket.
  3. Read and compare SPD data on a known-good machine (CPU-Z or an SPD reader) to check rank/density and timing entries.
  4. Try BIOS settings often overlooked: set command rate to 2T, raise DRAM voltage just a hair within the module spec, and loosen timings one step at a time.
  5. If you can get the board to boot with both sticks, run memtest86+ for several passes to confirm stability.

Why these steps matter: populating both channels changes electrical loading and timing margins. High-density chips, rank count differences, or odd SPD tables can prevent successful initialization in dual-channel mode even though each stick works alone. Some chipset/BIOS combinations are picky; a BIOS update or a change in command rate/voltage often fixes training failures.

If none of this helps, gather BIOS version and SPD dumps and pursue an RMA or swap for different modules (or a module pair on the motherboard QVL). When adjusting voltage, stay inside the manufacturer’s safe limits and monitor temperatures.

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Member Avatar for alc6379

Is the board dual channel? It sounds like that memory just might not be compatible with the board. I'd look at RMA'ing it, or at least trading a friend, etc.

Member Avatar for joshhighley

Yes, it's dual channel. It has a VIA KM266 Pro chipset. The memory from my other system that worked fine is Buffalo PC3200 DDR. I can get the TwinMOS to work with both DIMMs installed, but I have to manually set the BIOS DRAM Freq. to 133MHz instead of 166MHz. The TwinMOS worked fine in my other system as DDR at 166MHz

Thanks,

Josh

Member Avatar for alc6379

I would suspect an incompatibility, personally. Is swapping/returning for credit an option on that RAM?

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