Memeory Issues when OC'd

[cyber649]

I am still fairly new to this overclocking thing, so I need some help from the more experienced folks.

 

My setup:

 

Asus P6X58D-E

i7 950 @ 4.0Ghz (seems to be stable)

6gb of tripple channel XMS3 DDR3 1600MHz

H70 watercooling

Corsair 1000W PSU

Radeon 5870

 

And here are the settings I have for my OC setup:

 

BCLK Freq @ 175

CPU Voltage @ 1.35000 (cant go any lower or my system locks up)

DRAM bus voltage @ 1.50V (untouched)

CPU PLL @ 1.80 (untouched)

QPI/DRAM core volt @ 1.37500 (untouched)

 

If you need any further info, let me know and I will provide anything I can to help narrow my problem down.

 

So here is the issue I am having and it seems to be narrowed down to my memory. The issue that I am having is that if I set the DRAM to auto, it wants to put the memory at 1067MHz which is not what the memory is spec'd for if I am understand this right. When I set it manually when overclocking, the option I choose is 1735MHz if I remember right, because it is closet to the rated 1600MHz. What happens when I set it to that is that instead of showing 6GB of memory, it shows only 4GB of memory. When I go back and set it back to auto, it can detect all 6 gigs.

 

I want to know if there is something I need to set, such as dram voltage, dram core volt, timings etc. So that I can run it at full speed and than some, and run it stable. I had a complete lockup which makes me point the finger at the memory.

 

What can I do to resolve this, and has anyone else had this problem before?

 

Edited October 17, 2010 by cyber649

[RJR]

Try 21 X 191 = 4.011 Ghz OC then you will have 1528 Mhz option for the ram

 

or

 

20 X 200 = 4.00 Ghz OC and 1600 Mhz ram speed

 

or

 

try upping your vdimm to see if that helps at 1735 Mhz

 

or

 

etc...

[cyber649]

I will try out those right now and report back with the results in a few hours.

 

The one one I picked was 20x200.

[El_Capitan]

Try 21 X 191 = 4.011 Ghz OC then you will have 1528 Mhz option for the ram

 

or

 

20 X 200 = 4.00 Ghz OC and 1600 Mhz ram speed

 

or

 

try upping your vdimm to see if that helps at 1735 Mhz

 

or

 

etc...

I politely disagree. Keep the x23 multiplier, that's why you have the i7 950 in the first place. The lower BCLK means lower memory speeds, which allows for tighter RAM timings, which means better memory performance. What you have in those pics are already great if they're stable! Just make sure in the BIOS your DRAM bus voltage is at 1.65v. If you're not stable, manually set your DRAM frequency to 1050MHz and your UCLK to 2100MHz, then go into your DRAM Timing Control and set your timings manually to 8-8-8-24-1T, then start lowering to 7-8-8-24-1T, 7-7-8-24-1T, 7-7-7-24-1T, 6-7-7-24-1T, etc. When you crash during stability tests, loosen the timings back to where you were before, then proceed to lower the next number, i.e. 7-6-7-24-1T, etc. Once you're done with the first 3 numbers, you can start lowering the 4th... (since 7+6+7 = 20, add +1 to start there), 7-6-7-20-1T, 7-6-7-19-1T, etc.

 

It's a lot of time spent overclocking memory timings for minimal gains, so I don't spend too much time on it.

[Hemidare]

In the reviews i have been reading lately there is very little benefit to lower timings. They suggest going with the higher frequency for better performance all round. I agree you should increase the ram voltage to 1.65.

[El_Capitan]

In the reviews i have been reading lately there is very little benefit to lower timings. They suggest going with the higher frequency for better performance all round. I agree you should increase the ram voltage to 1.65.

Point me to those reviews! I always heard the opposite, lol. I've heard that most benchmarks test only the memory bandwidth and not the actual speed.

http://www.pcguide.com/ref/ram/timing.htm - Memory Bus

http://www.pcguide.com/ref/ram/timing.htm - DRAM Speed, System Timing and Overall Memory Speed

[cyber649]

I ran a couple benchmarks with 3dmark with the 23x and 20x multi, and the score was the exact same.

 

What performance gain in reality is there between the 20x and 23x multi with the i7 950?

[El_Capitan]

I ran a couple benchmarks with 3dmark with the 23x and 20x multi, and the score was the exact same.

 

What performance gain in reality is there between the 20x and 23x multi with the i7 950?

There isn't between multi's. It just helps to increase the CPU speed from the base clock. The performance gains from memory depend on the base clock (BCLK), either from increased bandwidth (Memory Bus) or faster memory timings.

 

So, with BCLK at 200 and multi at x20, your memory bandwidth is at 1600MHz.

With BCLK at 175 and multi at x23, your memory bandwidth is at 1050MHz.

 

Certain programs may benefit from higher memory bandwidth, but if you have more memory, that compensates for the lower bandwidth.

 

Now, faster memory timings, on the other hand, affect your system performance as a whole, and it doesn't matter what programs you're running.

[cyber649]

There isn't between multi's. It just helps to increase the CPU speed from the base clock. The performance gains from memory depend on the base clock (BCLK), either from increased bandwidth (Memory Bus) or faster memory timings.

 

So, with BCLK at 200 and multi at x20, your memory bandwidth is at 1600MHz.

With BCLK at 175 and multi at x23, your memory bandwidth is at 1050MHz.

 

Certain programs may benefit from higher memory bandwidth, but if you have more memory, that compensates for the lower bandwidth.

 

Now, faster memory timings, on the other hand, affect your system performance as a whole, and it doesn't matter what programs you're running.

 

That makes perfect sense.

 

Also, my system is running really stable right now as well. So, so far so good!

[AIinc]

If this is what you have (below), then yes, as said above, the DIMM voltage should be 1.65V,

But as far as your timings go, it will run just as well with the timings set to 7-7-7-20, as it will at 6-6-6-20

Bumping your numbers up or down by 1 wont get you any noticeable results. Only instability.

But setting the timings manually is important! (7-7-7-20 CR1/1T), and setting the memory with the proper voltage is very important, for it to run stable. You will gain very little overclocking your memory, compared to overclocking your CPU.

Plus, your divider setting for your memory, should be the closest setting to 1600MHz, without going over 1600MHz! Or only by a little bit!

 

1735MHz for your memory is a big overclock, and IMO way to much! DDR3 just doesn't overclock like DDR2 does!

I think this is your best option for getting 4GHz out of your CPU, stated above by El_Capitan.

"So, with BCLK at 200 and multi at x20, your memory bandwidth is at 1600MHz."

 

CORSAIR XMS3 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model TR3X6G1333C7 G

http://www.newegg.com/Product/Product.aspx?Item=N82E16820145250

 

Cas Latency: 7

Voltage: 1.65V

Multi-channel Kit: Triple Channel Kit

Timing: 7-7-7-20

[ccokeman]

I politely disagree. Keep the x23 multiplier, that's why you have the i7 950 in the first place. The lower BCLK means lower memory speeds, which allows for tighter RAM timings, which means better memory performance. What you have in those pics are already great if they're stable! Just make sure in the BIOS your DRAM bus voltage is at 1.65v. If you're not stable, manually set your DRAM frequency to 1050MHz and your UCLK to 2100MHz, then go into your DRAM Timing Control and set your timings manually to 8-8-8-24-1T, then start lowering to 7-8-8-24-1T, 7-7-8-24-1T, 7-7-7-24-1T, 6-7-7-24-1T, etc. When you crash during stability tests, loosen the timings back to where you were before, then proceed to lower the next number, i.e. 7-6-7-24-1T, etc. Once you're done with the first 3 numbers, you can start lowering the 4th... (since 7+6+7 = 20, add +1 to start there), 7-6-7-20-1T, 7-6-7-19-1T, etc.

 

It's a lot of time spent overclocking memory timings for minimal gains, so I don't spend too much time on it.

 

 

The CPU multiplier does not matter. It comes down to raw clock speed. To get higher performance you increase the bclock and lower the multi. 200x20 will put his memory right at 1600 with the optimal ratio. It looks like he has his memory set to auto and will need to manually set them for which you have provided a comprehensive answer

[Hemidare]

Point me to those reviews! I always heard the opposite, lol. I've heard that most benchmarks test only the memory bandwidth and not the actual speed.

http://www.pcguide.com/ref/ram/timing.htm - Memory Bus

http://www.pcguide.com/ref/ram/timing.htm - DRAM Speed, System Timing and Overall Memory Speed

 

Core i7 Memory Scaling: From DDR3-800 to DDR3-1600 google that and it should come up with some articles.

 

The one thing i would like to say is that overclocking the memory (except in rare instances) does not yield huge performance increases in everyday tasks. For my personal taste i like the higher mhz as apposed to lower latency and such. Just my .02.

Edited October 17, 2010 by Hemidare