PC3200 running slow at PC2700 speeds

[rocketbubba]

I just upgraded my Athlon XP 2500+ nForce2 system to an Athlon 64 3400+ nForce3 system. I carried over 1gb of Corsair XMS PC3200 (2 x 512mb sticks) to the new system. The problem is that on bootup the splash screen indicates that the ram is running at 333mhz. I ran the ram at that speed on my old system to match the FSB of the 2500 but now that I'm running the A64 I expected it to run at its specified speed. I looked in the Bios and it indicates that the "memclock" is 400. I'm wondering how I can get the ram to run at its full speed? Something in the Bios maybe? Thanks for any help.

 

[Remedy]

In the BIOS, force the DRAM setting to run @ "SPD" . Serial Port Detection. The DRAM's SPD would be seen as 400Mhz DDR. If not, update the BIOS on your motherboard. Which motherboard is it?

 

[obeseotron]

Do you only have those two sticks of RAM in the new A64? Manually setting it to DDR400, but having it come up DDR333 instead is what happens when you put 4 DIMMs in an Athlon64 system. Other than that scenario, I can't think of what else would cause a system manually set to 400, not to at least try to bootup at that speed.

 

[rocketbubba]

Thanks for the replies. The motherboard is a Chaintech VNF3-250 and I have 2 sticks of ram installed. When the computer boots the motherboard checks the ram and say the memory frequency is 333 mhz. I'll try setting the DRAM to SPD. Thanks again.

 

[Steve]

SPD = Serial Presence Detect.

Make sure you're using one DIMM per channel. The JEDEC spec dictates one unbuffered PC3200 DIMM per channel at full speed. More than that requires a stepdown in speed.

Newer A64 memory controllers are tweaked enough to allow multiple DIMMs @ DDR400, but as always with overclocking YMMV.

BTW, the lack of support for multiple DIMMs at DDR400 per channel is not a chipset or RAM controller issue, it's a JEDEC specification.