Can't pass stress test with ram

[starravier]

I fail the stress test in like 12 seconds when doing Large FFT. Could someone explain the difference?
When doing Small FFT's - stress CPU its fine but once i move on Large FFT's - stress some RAM i fail.
Faulty RAM? or something else. Im slowly learning how to OC my CPU, RAM is more confusing to me.

CPU: e6850 @ 3.7Ghz
Cooler: Ultra Carbon X7
Temp: While its being stressed in 68C

Could someone try to explain. Thanks

 

[djabhi003]

Its because your Ram isn't matching up with your FSB! I Mean when you overclock by changing the FSB, it affects the Ram as well! You must have seen the DRAM Ratio In your Bios Settings, that is the ratio between your FSB and the frequency at which your Ram Runs!

For Eg. 1 GB DDR2-6400 @ 800 Mhz means that the Ram runs at 800Mhz (Yes, u can go above that, but it depends on the quality of the Ram)!
But 800Mhz Ram means that the frequency is 400Mhz(1/2 Of The Specified) Because Ram nowadays is coupled(a pair)
So 800mhz = 2 x 400 Mhz! So in the Bios You Don't want to get the RAM Frequency above 400 Mhz if possible!

So if your DRAM ratio is 1:1, Den At 400 FSB Your RAM is at 400 Mhz And So You're Ok!
But If The Ratio Is 3:5,Den At 400 FSB Your RAM Will Be At 240 Mhz, Which Is Way Below 400 Mhz!

Seeing That you got upto 3.7Ghz, I think You have a really high FSB And The DRAM Ratio isnt Set Right! So Just Fiddle With The Ratio And Get It Right AccordinG To Your RAM!

If You Are Still Facing Problems Then You Hav To Set The Timings, So For RAM Timings Read Here, Excellent Guide:-
http://www.overclock.net/faqs/26706-info-ram-timings-dummies.html

And You Should Try Upping Your RAM Votagle Too, But Dnt Exceed 2.144 V, Thats a bit too high!

 

[djabhi003]

And What i meant by RAM Is coupled is not when you use 2 Rams, i Meant that a single chip of RAM Is coupled within, you will understand that when you read the guide!

And there's one more scenario like when your FSB is at 300 And DRAM Ratio Is 2:1, SO The RAM Is at 600Mhz i.e, 1200 Mhz Ram(Against 800 Mhz), which is an overclock!
That is how RAM Is Overclocked! But When you Get BSOD after overclocking your RAM(Like running Stress Tests) its because your RAM Isnt Stable!

Sometimes u have to set the timings, sometime you have to give it more juice(Voltage)!

If You have a higher Speed RAM Like DDR3 @ 1600 Mhz, Den that is seriously very good, because the Frequency could still go up till 800 Mhz(2 x 800 = 1600)!

 

[starravier]

Ok well FSB is 465MHz * Multiply 8
6-6-6-18 - 2T
Ratio is 1:1
The RAM is Kingston PC2-6400 (400MHz)

 

[henydiah]

Kingston PC2-6400 is this value or had headsprider ?

 

[geekapproved]

Ok well FSB is 465MHz * Multiply 8
6-6-6-18 - 2T
Ratio is 1:1
The RAM is Kingston PC2-6400 (400MHz)

There is your problem. You don't want to overclock your ram.

Your 800mhz ram is running at 930mhz. It won't last long at that speed. I'm surprised it hasn't burned up yet.

 

[starravier]

So what should i do?

 

[starravier]

Kingston PC2-6400 is this value or had headsprider ?

Did u mean a heat spreader? IF so then no.

 

[henydiah]

It's dangerous, overclock ram value

 

[starravier]

OK now im confused. i thought i was just overclocking my e6850. How did i end up overclocking my RAM as well

 

[djabhi003]

Look Your DRAM Ratio is 1:1 , And FSB is 465 Mhz! So Your Ram is Running At 2 x 465 = 930 Mhz! Which is way over 800 Mhz!

Decrease The FSB And Increase the mutliplier! Don't Go Above 400 FSB, Bcoz At Ratio 1:1 and FSB 400, Your Ram will be at 2 x 400 = 800 Mhz! Which is the correct frequency supported by your ram!

Its like a formula, Ram Frequency = [ 2 x (DRAM Ratio x FSB) ]

I Think upto 405 or 410 FSB, The RAM Might hold, but why risk it!

 

[wolfram23]

Or use a different ratio for the FSB:RAM...

 

[djabhi003]

Or Use a different Ratio.. Yes!

 

[jsc]

Sigh. Although everyone is correct with regards to your problem, there's a lot of misperceptions here. (All except you, Wolfram ).

And there's one more scenario like when your FSB is at 300 And DRAM Ratio Is 2:1, SO The RAM Is at 600Mhz i.e, 1200 Mhz Ram(Against 800 Mhz), which is an overclock!
...
If You have a higher Speed RAM Like DDR3 @ 1600 Mhz, Den that is seriously very good, because the Frequency could still go up till 800 Mhz(2 x 800 = 1600)!

dj, you have the right idea, but you have the ratios backwards. FSB:RAM ratio of 1:1 means that the FSB and RAM are running synchronomously. For DD2 RAM, the memory clock is twice the FSB freq. 1:1 is best for stability. 2:1 means the memory is running at half speed. The first number is the FSB. 1:2 means that the memory is running twice as fast as the FSB freq.

DDR3 doesn't work that way. DDR3 RAM has a RAM clock 4 times the FSB. With a 1:1 ratio using DDR3, a 400 MHz FSB freq produces a ram clock of 1600 MHz.

2.20 volts is safe for DDR2 RAM.

Running the RAM much faster than its rated speed will not damage the RAM. As you can see, it just will not work.

Star, you did not say what kind of motherboard you have. If you have a motherboard with an nVidia nForce6 or 7 chipset, you can uncouple the the mem clock from the FSC freq and set it independently. Otherwise, with the Intel chipsets, when you increase the FSB, you increase the memory clock.

You can try to set a lower FSB:RAM ratio like Wolfram suggested. Or you can try the other trick in the Overclocker's Toolbox.

Increase the RAM voltage to 2.2 volts. Then relax the memory timings. If your memory timings are 4-4-4-12, try relaxing them to 5's-15 (or if they are 5's-15, try 6's-18).

Going from 4-4-4-12 to 5-5-5-15 will decrease memory i/o about 3%, but will have an insignificant effect on overall system performance.
----------
Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz

 

[wolfram23]

^ Word. Voltage is the real killer, not speed. If it's not possible to get the RAM at it's rated speed but instead has to be faster (can't get a convenient FSB:RAM), running higher timings should work. Goes the other way too, slower speed with lower timings. Of course you COULD also try more voltage but, as mentioned, that's where you can run into problems. As an example, with DDR3 it's recommended to use 1.5V, with 1.65V being the max. I've run as high as 1.68V to get stability with high overclocks, but it's not really a good thing to do =P

 

[geekapproved]

OK now im confused. i thought i was just overclocking my e6850. How did i end up overclocking my RAM as well

Because your raising the fsb, which overclocks your ram.

The ratio your using (1:1) is causing your ram to run much faster than it's made to run, which will result in failure if it hasn't already.

You really shouldn't dabble in overclocking without understanding how it works first.

 

[jsc]

As an example, with DDR3 it's recommended to use 1.5V, with 1.65V being the max. I've run as high as 1.68V to get stability with high overclocks, but it's not really a good thing to do =P

It's one thing to do that on a Core2 motherboard and another to do it on a CPU with an itegrated memory controller.

 

[geekapproved]

^ Word. Voltage is the real killer, not speed. If it's not possible to get the RAM at it's rated speed but instead has to be faster (can't get a convenient FSB:RAM), running higher timings should work. Goes the other way too, slower speed with lower timings. Of course you COULD also try more voltage but, as mentioned, that's where you can run into problems. As an example, with DDR3 it's recommended to use 1.5V, with 1.65V being the max. I've run as high as 1.68V to get stability with high overclocks, but it's not really a good thing to do =P

"with ddr3 it's recommended to use 1.5v with 1.65v being the max"


Where did you get that from?? There is 1.8v DDR3, that works perfectly fine in certain systems.

I think what you meant to say is "With Sandy Bridge cpu's, it's recommended to use 1.5v DDR3 with 1.65v being the max".

Your welcome for the correction.

 

[wolfram23]

"with ddr3 it's recommended to use 1.5v with 1.65v being the max"


Where did you get that from?? There is 1.8v DDR3, that works perfectly fine in certain systems.

I think what you meant to say is "With Sandy Bridge cpu's, it's recommended to use 1.5v DDR3 with 1.65v being the max".

Your welcome for the correction.

Well I've looked over the documentation (http://download.intel.com/design/processor/datashts/322164.pdf) many times, but I guess they changed it in one of the revisions. Good call though. I remember when they had the VTT max as 1.21 (iirc) but now it's 1.4V. Anyway, I guess I have more wiggle room for OCing than I thought.

 

[djabhi003]

Thanx jsc!
i really know when am doing it.. .. i mean, i got my e4500 upto 3 Ghz and did the Ram ratio, and timings perfectly.. But when i put that into words, KABOOM! ...

And, Upping the voltage to 2.2 on a PC2_6400 Ram isn't advisable! 2.14 would be the max i would suggest somebody, But My DDR2_400 runs fine at 2.08 V!

 

[geekapproved]

Djabhi003, there are many DDR2 sticks that are 2.2v stock.

I think what you meant to say is it's not advisable to run 1.8v DDR2 at 2.14v. Right?

 

[starravier]

Star, you did not say what kind of motherboard you have. If you have a motherboard with an nVidia nForce6 or 7 chipset, you can uncouple the the mem clock from the FSC freq and set it independently. Otherwise, with the Intel chipsets, when you increase the FSB, you increase the memory clock.

You can try to set a lower FSB:RAM ratio like Wolfram suggested. Or you can try the other trick in the Overclocker's Toolbox.

Increase the RAM voltage to 2.2 volts. Then relax the memory timings. If your memory timings are 4-4-4-12, try relaxing them to 5's-15 (or if they are 5's-15, try 6's-18).

Going from 4-4-4-12 to 5-5-5-15 will decrease memory i/o about 3%, but will have an insignificant effect on overall system performance.

OK well im using a p5k-e mobo
ok well now its

415x9 = 3735Ghz

Yet im still failing...should i drop it to 400 to keep it 1:1 or should i up the voltage?

 

[geekapproved]

Neither. Your not getting it.

You need to change the ratio so that the ram is running at or below 800mhz.

 

[djabhi003]

Well There are boards who don't support changing DRAM Ratio(I had one).. Maybe His is one lyk That, is it ?

And Yeah, I Meant Running 1.8V Ram @ 2.2v Is Very Un-advisable!

 

[geekapproved]

I guarantee his board has fsb/dimm ratio adjustments.

It's common sense that you don't run 1.8v ram at 2.2v.