DDR upgrade on P4B266-C

[Yves Leclerc]

I currently have a P4B266-C motherboard which has 2 x 256MB DDR 266Mhz
modules. I have been successfully running Windows XP Pro for @ 2 year. I
am now receiving "IRQL_NOT_EQUAL..." stop error messages during the XP Pro
boot up. I have found out that this may be a RAM problem and it was
suggested that I replace the RAM modules. I do not "over-clock" my
motherboard or processor (P4 1.60a)

My question is: Can I replace the 266Mhz RAM modules with higher rated RAM
modules (i.e. 333Mhz or 400Mhz)?

 

[Paul]

I currently have a P4B266-C motherboard which has 2 x 256MB DDR 266Mhz
modules. I have been successfully running Windows XP Pro for @ 2 year. I
am now receiving "IRQL_NOT_EQUAL..." stop error messages during the XP Pro
boot up. I have found out that this may be a RAM problem and it was
suggested that I replace the RAM modules. I do not "over-clock" my
motherboard or processor (P4 1.60a)

My question is: Can I replace the 266Mhz RAM modules with higher rated RAM
modules (i.e. 333Mhz or 400Mhz)?

I know people don't like waffle type answers, but from the Micron
datasheet we get:

http://download.micron.com/pdf/datasheets/dram/ddr/256Mx4x8x16DDR.pdf

Clock cycle time CL = 3 tCK (3) 5ns min 7.5ns max
CL = 2.5 tCK (2.5) 6ns min 13.0ns max
CL = 2 tCK (2) 7.5ns min 13.0ns max

This means basically, you are covered from 5ns = 200MHz = DDR400 to
13ns = 77MHz = DDR154 (i.e. DDR200 with some margin).

Some Hynix datasheets are here:
http://www.hynix.com/datasheet/eng/...MS=256&ME=511&RAM_NAME=DDR SDRAM&SUB_RAM=256M
http://www.hynix.com/datasheet/pdf/dram/(1)HY5DU564(8,16)22DF_D(Rev0.1).pdf

System Clock Cycle Time CL = 3 tCK 5ns min 10ns max

This covers 5ns = 200MHz = DDR400 to 10ns = 100MHz = DDR200

Based on this small sampling, it would seem the design intent is
for a DDR400 to cover all the way back to DDR200. (Presumably
there is a spec on jedec.org that covers what the min speed
requirement is.)

Hynix has some chips binned for DDR500 operation, but I cannot
find a datasheet for them. I would be curious whether a PC4000
DIMM can still run at DDR200 (it should, but stranger things
have happened). The problem is, JEDEC defines up to DDR400,
so it is hard for any company officially offering parts at
speeds higher than that, to acknowledge them. The Hynix site
is not easy to navigate, in terms of finding what you want.

HTH,
Paul