Phenom Memory Issue with Overclock

[LoneNinja]

I've got a Biostar 790GX motherboard(I'll grab exact model number if needed) and 2x2Gb Gskill DDR2 1066 memory paired with a Phenom 9850.

I overclocked the Phenom to 3.0Ghz without any problems and its been stable in Prime95 for about 2 hours, and has been loaded 100% usage with 3ds max more than once now for several hours at a time rendering and I've played games. However my problem is that my motherboard is defaulting my ram to 800 instead of its rated 1066. When I manually adjust it to run at 1066 my computer becomes unstable and Prime fails in a matter of seconds every time I try and run it. The strange thing is that the computer was fully stable with the Phenom at stock and the memory running at 1066, and I was using the memory at 1066 previously to this paired with a 7750.

Does anyone have an explanation for me as to why I need to down clock my memory to remain stable while I'm only changing the multiplier and voltage to overclock the cpu?

 

[Flipped Gazelle]

Try increasing the voltage for the RAM to 2.0v.

 

[F1shF4t]

If his RAM is rated at 1.8v, increasing the voltage might be not so good for its life expectancy.

Does it do the same thing at say 2.8ghz? Isn't the mem controller clocked off the nb (or uncore & L3) clock on Phenoms? so it wouldn't seem like ocing the cores too high would make the mem controller be unstable like it happened on the K8s.

 

[Bandit1]

If i remember right,early bios versions had the problem of not retaining some settings on oc.

I have the exact same setup,A2+(but with upgraded cpu now),although i am not hard into oc'ing.You may find a more precise answer at rebelshaven for that specific motherboard.I have ram set at 2.1v because the board is undervolting some for me,nearly.1v.
I have the same memory and it is fine @1066 setting,but i dialed in all memory timings as well.If you download a program called memset 4.0,it will show you alot of the spd timings,moreso even than cpu-z.Set them as close as possible the same in bios for 1066.

Last but not least,you may need a bump of northbridge voltage and i assume your overclock is strictly thru multi bump,not bus.

 

[Flipped Gazelle]

Originally posted by: Dark Cupcake
If his RAM is rated at 1.8v, increasing the voltage might be not so good for its life expectancy.

Does it do the same thing at say 2.8ghz? Isn't the mem controller clocked off the nb (or uncore & L3) clock on Phenoms? so it wouldn't seem like ocing the cores too high would make the mem controller be unstable like it happened on the K8s.

Sometimes, AM2 boards will undervolt the RAM, so I figure it's pretty safe to test at 2.0v.

Isn't the mem controller clocked off the nb (or uncore & L3) clock on Phenoms?

Yup.

 

[Modular]

When you say that you manually set the RAM to 1066, you do realize that's only a divider setting and not the actual memory speed right?

Here's a neat chart that can help you understand what speed you are actually running your memory at.

 

[Smoove910]

Originally posted by: Dark Cupcake
If his RAM is rated at 1.8v, increasing the voltage might be not so good for its life expectancy.

Not many 1.8v 1066 sticks out there to choose from. Typically the 1.8v sticks are 800mhz. Run @ 2.0/2.1 and see what happens.

Raise your chipset voltage up a click as well

 

[LoneNinja]

I bumped both my chipset and memory voltage up and its stable now.

 

[cusideabelincoln]

Originally posted by: Modular
When you say that you manually set the RAM to 1066, you do realize that's only a divider setting and not the actual memory speed right?

Here's a neat chart that can help you understand what speed you are actually running your memory at.

This was my suggestion. When you're setting the RAM to run at 1066 in the BIOS, you are actually setting a divider. And since you are overclocking, I bet your RAM is actually runing faster than its rated speed, that is if you're increasing the FSB at all.

You can check the real speed of the RAM with CPU-Z under the "Memory" tab. Just look at the "DRAM Frequency" and multiply it by 2 to get the rated speed.