VS1GBKIT400 + Shuttle AB60R I865 + Celeron 400 MHz FSB = DDR266??

[keith721]

Processor is a 2.4 GHz Celeron, Socket 478, 400 MHz Front Side Bus.

Motherboard is a Shuttle AB60R with Intel 865 + ICH5 (Springdale) chipset.

Memory is Corsair Value Select VS1GBKIT400, 2 DIMMS x 512 MB, running in dual-channel mode.

 

I have loaded the latest BIOS to the motherboard, but it insists on running the RAM at DDR266. The BIOS doesn't offer either DDR333 or DDR400 as options for manual overrides, only AUTO or DDR266.

 

I don't understand :confused: The BIOS sets the FSB at 100 MHz times a 24 multiplier. I would expect the RAM to run at either DDR400 or possibly DDR200, but not DDR266. Is this a BIOS fault, or am I missing something totally obvious?

 

Thanks in advance for your constructive comments or suggestions.

[RAM GUY]

This is a chipset limitation.

If the FSB of your CPU is 400 For Intel and 100 MHz for AMD, the memory speed supports only DDR 266.

If the FSB of your CPU is 533 For Intel and 133/166 MHz for AMD, the memory speed supports DDR 266/333

If the FSB of your CPU is 800 MHz for Intel and 200 MHz for AMD, the memory speed supports DDR 333/400

[keith721]

RAM GUY:

 

Thanks for the confirmation. Guess I'll need to get an 800 MHz FSB P4 to enjoy the full DDR400 experience, then. :sigh!: Would you have any links to technical reference documents, explaining this limitation? I don't doubt you in the least, I'd just like to have a better understanding of the "why".

[RAM GUY]

I am not sure these are public, but you would need to get the Data Sheets for the respective chipset and or CPU if its AMD 64.