dual channel ddr bus speed drops 400 -> 266 MHz

[Frank]

Hello,

I have an ASUS P4P800deluxe motherboard. One channel of memorybanks was
filled with 2x256 MB Corsair twinx memory modules. The bus (FSB?) worked
at 400 MHz as was shown by the BIOS messages. Recently I added another
pair of Corsair twinx memory modules, 2x512 MB. Now the bios reports the
bus speed is working at 266 MHz. The new dimms are ddr pc3200 (400MHz)
modules, so why is the bus speed dropping to 266 MHz??

I have a feeling that my computer is now slower then before. Is it
expected that one notices a decreased performance by a bus speed
decrease from 400HMz to 266MHz??

Regards,
Frank

 

[daytripper]

Hello,

I have an ASUS P4P800deluxe motherboard. One channel of memorybanks was
filled with 2x256 MB Corsair twinx memory modules. The bus (FSB?) worked
at 400 MHz as was shown by the BIOS messages. Recently I added another
pair of Corsair twinx memory modules, 2x512 MB. Now the bios reports the
bus speed is working at 266 MHz. The new dimms are ddr pc3200 (400MHz)
modules, so why is the bus speed dropping to 266 MHz??

I have a feeling that my computer is now slower then before. Is it
expected that one notices a decreased performance by a bus speed
decrease from 400HMz to 266MHz??

Regards,
Frank

It's not unlikely that one would notice a 30% loss of memory bandwidth.

Have you tried installing just the Corsair dimms alone to see if this is truly
a population-driven bios phenomenon, and not the result of using the wrong
speed dimms?

 

[Gordon Scott]

Hello,

I have an ASUS P4P800deluxe motherboard. One channel of memorybanks was
filled with 2x256 MB Corsair twinx memory modules. The bus (FSB?) worked
at 400 MHz as was shown by the BIOS messages. Recently I added another
pair of Corsair twinx memory modules, 2x512 MB. Now the bios reports the
bus speed is working at 266 MHz. The new dimms are ddr pc3200 (400MHz)
modules, so why is the bus speed dropping to 266 MHz??

I have a feeling that my computer is now slower then before. Is it
expected that one notices a decreased performance by a bus speed
decrease from 400HMz to 266MHz??

Regards,
Frank

read your manual closely, installing more than 2 dimms quite often lowers
the the buss speed. You also want to refer to the manual as to single and
double sided dimms in the specific slots.