Just because timing is more relaxed or "less demanding" it means not that RAM can work at that speed. You should check the RAM manual, specs from manufacturer or the SPD settings (CPUz does that, incidentally). If it wasn't listed to work at 333 it will not.
It is likely that newer and cheaper RAM will not maintain backwards compatibility, and if the DIMMS are not exactly overclocker material it's very unlikely they have multiple SPD settings, voltage levels and so on.
Thanks for this answer. I checked with cpuz that 333 is allowed by spd. So this can not be the reason for such a beaviour. On other boards (for example Gigabyte) to take slower timings helped to make system more stable. I think its very strange that it ist not even booting to BIOS with manual timings.
the reasen for changing the timings is the following: The Sytem worked (in Office) for about two years. Last tuesday it had had two or three bluescreens/different Problems (they are not shown in Eventviwer).
The strange thing was that after shuting down/pulling the plug and restarting the system the screen does not show anything (not even POST). (Changing the position of the BIOS Jumper helped after some tries).
One possible reason for this could be a problem wihth the memory. So I tried to change the timings
I use two Modules of the following type (cpuz):
DIMM # 2
SMBus address 0x53
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) Samsung (CE00000000000000)
Size 1024 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number M3 78T2953EZ3-CF7
Serial number 7508ACC0
Manufacturing date Week 26/Year 07
Number of banks 2
Data width 64 bits
Nominal Voltage 1.80 Volts
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 4.0-4-4-12-16 @ 266 MHz
JEDEC #2 5.0-5-5-15-20 @ 333 MHz
JEDEC #3 6.0-6-6-18-24 @ 400 MHz
The two things I changed concerning the instability was: BIOS update vom 267 and change of the Banks of the Modules. Since now I didn't hear about new Problems but its not too long ago since I made the changes.
The MB supports 333 and 400 as per specs.
If you have set the RAM to 333 5-5-5-20 (IIRC) then it should have worked. Swapping slots is a good idea, but, in general, components can make other components not work. Since the PC was already unstable, it might have pushed it over the edge.
If you are still trying to fix the issue, I recommend running MemTest overnight. That will eliminate doubts on RAM. And if it doesn't, your (pretty much) last resort would be to swap the RAM for another PC with equivalent DIMMs and see which borks. If the RAM works in the board at 333, it's the RAM, and viceversa.
Note that lowering frequency doesn't fix stability unless it's memory speed related, if you have stability issues you should try looking into other sources - MemTest for the RAM, a swap of the DIMMS and, not least, cooling and power. A fading power supply does very odd things to a PC.
Message was edited by: Ndi (spell)