1.65v modules too much for P55? 1156/i7, i5

[Derek Hanson]

So Intel's official stance is that anything over 1.6v could damage the cpu..

However there are a lot of dimm's for sale out there that claim to be i7/i5 compatible but specify 1.65volts to operate...

G. Skill is one of few brands that offer 1.5-1.6v dimms..

So what's a guy to do? I'd prefer Corsair or Mushkin but does it really matter? folks seem to have hit and miss reports on G.Skill.. Long-term (3+years) reliability and stability is paramount for me, OC potential is not.

I always avoided G.Skill brand in the past.. reminds me always of G-Fresh from Orgazmo..

My Specs for upcoming system...

Intel DP55WG board
Intel i7 860
4GB DDR3 1600MHz of...
ATI 5850 of whatever flavor is in stock
SSD to be determined
1TB WD black
various odds and ends
Antec EarthWatts 650
into lian-li a05n

Thanks pals!

 

[VirtualLarry]

Nothing wrong with GSkill memory. I much prefer them to OCZ.

 

[Marmion]

If you're not overclocking, there's no point in 1600Mhz ram, 1333Mhz is default. 1600Mhz ram will run at 1333 unless you overclock or change bclk and memory dividers.

 

[WaitingForNehalem]

My Corsair RAM runs at 1.5V.

 

[Derek Hanson]

I guess I assumed that if the specs of the mobo say that 1600 is the native memory speed then there is little if any OC'ng going on. I was also assuming that increasing the speed to 1600 doesn't necessarily change anything in CPU-land as far as base clock etc..

I could be wrong (probably)

 

[Yellowbeard]

So Intel's official stance is that anything over 1.6v could damage the cpu.

The Intel recommendation is to not exceed 1.65v, not 1.6v. That's why all the faster kits are 1.65v rated which is safe.

 

[Derek Hanson]

Unbuffered, non-registered single- or double-sided DIMMs with a voltage rating of less than 1.6 V. Using a DIMM with a voltage rating higher than 1.6 V may damage the processor.

The above taken from Intel memory compatibility page for the DP55WG board
--> Link

 

[n7]

I guess I assumed that if the specs of the mobo say that 1600 is the native memory speed then there is little if any OC'ng going on. I was also assuming that increasing the speed to 1600 doesn't necessarily change anything in CPU-land as far as base clock etc..

I could be wrong (probably)

Don't assume.

Manufacturers love marketing that their boards can do stupidly high RAM speeds, when in fact a lot of the time, only the very best overclockers & RAM kits will achieve those speeds (think Gigabyte's DDR2-1333 marketing garbage)...

For s1156, DDR3-1333 is native speed.
Anything higher is either achieved thru overclocking or via a higher available ratio.

However, your i7 860 should be able to do DDR3-1600 @ stock; i5 750 will be only DDR3-1333 max @ stock.

Either way, if you aren't OCing, please look for something 1.5v rated, or at least realize that most higher end kits require you to set vDIMM/ratio/timings to achieve their rated speeds...

 

[victorm]

I have G.Skill in my custom rig and they do fine at 1.5v hope that helps.

 

[Ben90]

Im pretty sure that link with the mobo is a typo. Its listed absolutely everywhere else (including every other intel documentation) as 1.65v.

 

[punjabiplaya]

running g.skill ddr3 2000 @ 1.65v just fine. just set to the correct xmp profile and (depending on the board/bios) put in 1.65v into the vdimm.

 

[gmjimmy]

FYI
I found this on this Anandtech article.
http://www.anandtech.com/memory/showdoc.aspx?i=3589

Well, Intel officially released their recommended memory voltages for the Core i7 several months before launch with 1.50V as the recommended base voltage and 1.65V as the suggested maximum along with 1.35V for VTT (QPI) maximum.

 

[ekoostik]

running g.skill ddr3 2000 @ 1.65v just fine. just set to the correct xmp profile and (depending on the board/bios) put in 1.65v into the vdimm.

If you turn on XMP on in i7 860 for any RAM with greater than 1600 MHz frequency you will lose Turbo (you may be able to bring it back by OCing your CPU) and will likely have to turn on power saving features and sleep states (EIST, C-states) although it's not a bad idea to specifically enable these anyway, if you want them on.
Some people are ok with loosing Turbo at the expense of getting RAM that runs at 2000 or more MHz. But wanted to make sure you knew.

n7 put it best:

For s1156, DDR3-1333 is native speed.
Anything higher is either achieved thru overclocking or via a higher available ratio.

However, your i7 860 should be able to do DDR3-1600 @ stock; i5 750 will be only DDR3-1333 max @ stock.

Either way, if you aren't OCing, please look for something 1.5v rated, or at least realize that most higher end kits require you to set vDIMM/ratio/timings to achieve their rated speeds...

You can even find RAM that runs at less than 1.5V. G.Skill has an eco line that takes 1.35.

 

[RussianSensation]

You can always relax the timings and run the ram at 1.6V. For example, my G.skill kit is rated at 1.60V @ DDR3-1600 CL7 timings, but can do that at 1.568V. Just because it's rated at 1.65V, doesn't mean you need to apply that much voltage.

Most G.Skill ripjaws will do DDR3-1333 CL8 at just 1.5V

 

[Yellowbeard]

I have run several 1600 kits so far with the 750 using the XMP profile. Since the memory multi maxxes out at 10, the XMP profile sets a 160 BClock, 1.65v memory voltage, and 1.15v on the QPI. Obviously I can't comment on long term longevity as this stuff is all new but all is well so far.

 

[ekoostik]

I have run several 1600 kits so far with the 750 using the XMP profile. Since the memory multi maxxes out at 10, the XMP profile sets a 160 BClock, 1.65v memory voltage, and 1.15v on the QPI. Obviously I can't comment on long term longevity as this stuff is all new but all is well so far.

With the i5 750's, what has it done to the CPU multiplier? Every one I've seen so far compensates for the increased BCLK by lowering the CPU multiplier to 17. This means that you're running at a constant 2.72 GHz with no Turbo. As opposed to 2.66-2.79GHz with the ability to turbo up to 3.20GHz.