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Problem - AMD 955 BE w/ 1600mhz memory - Page 2

post #11 of 14

Set the CPU-NB voltage higher without the initial raise to 2400Mhz.  Find your own stable voltage.

 

But the problem may not be the CPU-NB, it may be the RAM itself.

If the first pair will not even run at 1333Mhz (loose timings?) then there is probably a defect with it.

It is not likely that the second pair will be able to run stable at 1600Mhz due to the low binning of generic DDR3-1333 CL9 memory kits.

 

So 1600Mhz operation might not be reasonable for you.  I'd recommend taking advantage of warranty on kit #1 while you can.

post #12 of 14
Thread Starter 
Quote:
Originally Posted by xd_1771 View Post

Set the CPU-NB voltage higher without the initial raise to 2400Mhz.  Find your own stable voltage.

But the problem may not be the CPU-NB, it may be the RAM itself.
If the first pair will not even run at 1333Mhz (loose timings?) then there is probably a defect with it.
It is not likely that the second pair will be able to run stable at 1600Mhz due to the low binning of generic DDR3-1333 CL9 memory kits.

So 1600Mhz operation might not be reasonable for you.  I'd recommend taking advantage of warranty on kit #1 while you can.

Already RMA'd the set of Snipers because I thought that was the problem also.

What do you mean just raise the voltage? I thought the CPU NB had to be *3 whatever half of whatever you are running your memory at. So if I was aiming for 1600 it would have to be 2400, or if I run the memory at 1333 I set the CPU NB to 1800.

I am receiving a pair of 1600mhz memory on monday/tuesday (Ripjaw X series) and will attempt to get stock timing out of them then also.
post #13 of 14

That is a recommended value that has to do with memory controller spec in order to avoid bottlenecks (i.e. "ideal RAM:CPU-NB ratio"), as stated in an official AMD document that was find not too long ago by dixson01974.  AMD sets the max spec of RAM at 1333Mhz because the before-DDR clock of 667Mhz is exactly the 2000Mhz CPU-NB divided by 3.  When you are running 1600Mhz, which is technically beyond the default rated spec, you need to have a 2400Mhz NB (800Mhz before-DDR clock x3) to avoid any bottlenecking of the bandwidth; this may also involve a CPU-NB overclock.  Thus it is not within AMD's default spec.  This does not mean that you cannot take the IMC clock to 2400Mhz safely, or further.  This also This does not mean that higher CPU-NB does not provide even better performance; think of it as an "at least".  There is no link between specific CPU-NB speed and RAM speed with stability.  You can run any combination just fine; just one is more ideal than the other.

 

Also, newer integrated memory controller designs (i.e. on the FX processor) that improve internal "CPU-NB IPC" (or you could so call it) in addition to power consumption/voltage do not follow the same "ideal RAM:CPU-NB" ratios.

post #14 of 14
To answer your original question, there is no guarantee that your CPU/mobo/RAM will OC to 1600 MHz. though many will. All you can do is try various settings/combinations to see what will actually work with your hardware.

The online PC Tutorials are based on people's experiences and opinions. Every combination of CPU/mobo/RAM is different and thus they OC differently. I have a 965 BE that does not like the NB above 2200 MHz. but it OC's to 4.0 GHz. at the default voltage. Other folks have reported similar NB frequency limitations - which do not undermine performance in any tangible manner. It is what it is when you are OC'ing.
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