Voltages at DDR3 1600

[pinaklonkar]

I am quite sure this topic must have been discussed somewhere here before but I could not find what I was looking for.

Specifications-

Intel i7-860 CPU,

Asus P7P55D plain motherboard,

OCZ Gold 8GB memory OCZ3G1600LV4GK http://www.ocztechnology.com/products/memory/ocz_ddr3_pc3_12800_gold_low_voltage_dual_channel,

1 x HIS HD Radeon 5850 gpu

Corsair 650W power supply.

Question -

When I set the memory frequency at DDR3-1600, I see that the DRAM voltage which is set to AUTO shows 1.8 volts!! I never noticed it until today. All this time the computer is functioning without any trouble. But I remember talking to OCZ support the other day and he told me to set the voltage at 1.65V and timing at 8 8 8 24 (CAS-TRCD-TRP-TRAS). When I set the memory frequency at AUTO, it runs at DDR3-1067 and the voltages drop to 1.5V.

What's happening here, and why? and what should be my worry-free optimal settings if I want to run the memory at the highest possible speed? Would it affect my CPU cores' temperatures in any way?

What are these low voltage memory modules anyway?

 

[JDFan]

The memory controller chip on the i7 runs at a default speed of 1067Mhz. and so if set on auto that is what the memory will be set to - also the default voltage spec for ddr3 is 1.5V so it will also default to that voltage. - In order to get it any higher the settings must be done manually!

And the LOW VOLTAGE tag is just a marketing gimmick to get people to buy those modules (since the early Intel MOBOs had problems with melting sockets if the voltage was set higher than 1.65 volts so many consumers are looking for low voltage in order to avoid this so will buy more modules that stick those 2 words in the spec !)

 

[pinaklonkar]

JDFan,

Small series of questions.

a) So with my current specs, is there any benefit in manually setting the frequency at 1600MHz?

b) If yes, should I also then manually set the voltage to 1.65V? (since auto makes it 1.8V).

c) If no, should I just stick to both AUTO and live with it? how much of a performance am I missing out on?

d) Is 1.8V safe at my current specs?

Thank You. And the low-voltage gimmick was well put. Thanks. OCZ will never hire you

 

[pinaklonkar]

http://www.xtremesystems.org/forums/showthread.php?t=212588

Interesting thread.

 

[ekoostik]

The memory controller on the i7 9xx chips runs at 1067 MHz by default. The i7 8xx chips will default to 1333 MHz. However, depending on how you loaded defaults in BIOS it may have set to a safer speed of 1067, or perhaps the info coded onto the RAM sticks caused the 1067 speed.

With an i7 8xx CPU you can run the RAM at 1600 MHz by changing the DRAM SPD (memory multiplier) to x12 (or some BIOS allow you to pick the speed directly). Yes you should also handkey the timings and set the V to 1.65V. That is the absolute max spec on the last couple Intel architectures. Anything higher than that can lead to problems, especially with the MCH on the Lynnfield (i5 7xx, i7 8xx) CPUs.

Or you could run them at 1333 and set the V to 1.5V and try to tighten the timings.

1.8V is not safe for the long run.

As to whether 1600 MHz makes much difference, outside of benchmarks the answer is not really: http://www.tomshardware.com/reviews/core-i7-870-1156,2482.html

 

[pinaklonkar]

"tighten the timings" - can you elaborate? should I move it up to 8 8 8 24, or 7 7 7 20 ?

thanks

 

[ekoostik]

Start at 8 8 8 24, which is what they're specced at. Then move down to 7 7 7 20 and see if it is stable.

 

[pinaklonkar]

Best answer selected by pinaklonkar.