i have a strange proble. I bought Asus p5g41t-lx3 and put Corsair 8GB 1600mhz ram into it and what happend? Ram works good bat on 800mhz, wtf???? Can somebody help me overclocking it to 1333mhz??? my main problem is that when i increase FSB to 333 (=1333mhz) i have to edit these tRT, tCAS ecc....
Pleade help, thanks.
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Motherboard manufacturers are often extremely vague about what the actual DRAM speed is because DDR SDRAM can be expressed as either the bus frequency or the transfer frequency. The bus speed is half that of the transfer frequency.
The difficulty is that they overlap, there are DDR3 specifications for 400Mhz (800 MT/s) and 800Mhz (1600 MT/s) and many memory modules are rated to work at both speciciations.
That's the bus speed (data is transferred on two edges of the clock, hence Double Data Rate). You should be able to get it running at 533x2=1066 stably, try that first. 667x2=1333 is an overclocked profile but from my experience the LGA 775 platform (all chipsets) had a horribly hard time supporting high speed memory.
If your processor is designed for a 266Mhz FSB (1066MT/s because the FSB transfers 4 times per clock) then you should leave the FSB at 266 and change the DRAM to FSB ratio. Please note that just like DRAM speeds the FSB speed can be expressed as both a bus frequency and a transfer frequency. Thus you will need to check your motherboard manual to see if you are comparing bus speeds or transfer speeds, the difference is important and will change the ratio by a factor of 2. For the purposes of this, I will use bus speeds. If the DRAM to FSB ratio is 2:1 that means that the DRAM clock will be 533 when your FSB clock is 266. Doubling that gives you a 1066 transfer rate, which is what the board was designed for and is what I suggest that you use. Changing the FSB to 333 gives you an FSB transfer rate of 1333 as well as a DRAM transfer rate of 1333 which is what you tried. However, when you do this you are not only overclocking your memory, you are also overclocking your CPU.
Thus, I want you to see if your motherboard has a 2.5:1 (or 5:2) memory ratio and try that while leaving the FSB at 266. This will let your memory hit 667Mhz without pushing your CPU into a possibly unstable region of operation.
Next, I want you to see if there's a 8:5 memory ratio. Running this with the FSB set at 333Mhz (if you have a CPU that calls for that, or if you want to test a stable CPU overclock) will put the memory at 533Mhz which is what the motherboard is said to support.
None the less, you can always run the DRAM at 400Mhz as most Core2 CPUs will not benefit from anything faster
But 800 is in bios sooo in cpu-z i see 400 sooo it's not right, am i correct?
can you show us pictures of cpu-z? that way we can get a better idea of what we are looking at here... just take a picture of the memory tab and one picture of one of your memory sticks in the spd tab. ill help you with the best of my abilities.but yes, you are correct.
what cpu are you running? and can you take a picture of BIOS overclocking? so we can get an idea of what we need.. but it looks like everything is ok to run. just might need some timing and ratio changes.