Question about memory

[Powermoloch]

I'm out of the loop of PC memory and could use your guys help and experience.

I'm shopping around to add more ram into my rig. What will happen if I grab a set of DDR3 1600 ram with 9-9-9-24 1.65 v w/ 9-9-9-27 1.5 sticks that are in my comp?


Also will DDR3 1600 downclock to 1066?

thanks !

 

[NXIL]

Also will DDR3 1600 downclock to 1066?

thanks !

Yes. Set in BIOS manually if is does not happen automatically.

What will happen if I grab a set of DDR3 1600 ram with 9-9-9-24 1.65 v w/ 9-9-9-27 1.5 sticks that are in my comp?

You will anger the RAM gods. ALWAYS use the SAME model memory from the SAME manufacturer with the SAME XMP values, unless you want to have a lot of fun trying to set all that by hand. And you like blue screens and errors on MEMTEST.

Good RAM is cheap; you should be able to buy a matching set easily.

Or: right now, 2 x 4GB sets are about $40. This is insanely cheap. "8GB ought to be enough for anybody!" (Sorry Bill Gates....)

I have seen 2 x 8GB very cheap too.

Anyway, don't mix and match, unless you like the pain.

 

[jimmybgood9]

The 1.65 v sticks could be identical to the 1.5 v sticks, except that the manufacturer is giving it's imprimatur to go ahead and overclock them. Theoretically, raising the voltage on a semiconductor allows you to run it successfully at a higher speed (or lower latency). So the 1.5 v sticks may even outperform the 1.65 v sticks if you run them at 1.65 v. Or maybe they can't handle the 1.65 v and will burn out. Certainly, running RAM at higher voltages consumes more power and generates more heat, but not a whole lot.

My advice would be to get new RAM that matches your old RAM as closely as possible.

With a decent motherboard, you shouldn't have to underclock the RAM very much, you just set the multiplier as high as necessary to get the RAM to go as fast as it's rated or as close as you can get. DDR3 RAM is cheap. If your system is short on it, it will help. I guess that's a tautology , isn't it?

 

[Powermoloch]

alright, this is informative :thumbsup: Thanks everyone !

 

[KingFatty]

The 1.65V sticks may be rated by the manufacturer to run at the lower voltage when you drop down their speed. I know my RAM is like that, and I intentionally run it at the lower speeds. Maybe you can see the SPD info for the RAM, they may list different voltages for different speeds, so that your motherboard can automatically set all the ram to the same lower speed/lower voltage.

 

[Blain]

If I were shopping for high quality memory, I would use the following parameters as a guide...

* DDR3 rated at 1.5v or lower
* DDR3 rated at the lowest CAS I could afford
* DDR3 rated at the highest clock speed I could afford
* Limit the scope of my purchease to G.Skill, Mushkin, Corsair XMS or Crucial (non-Ballistix)

While not wavering on the voltage point, I would balance the other issues with my budget.

Remember my goal is not pure "benchmarking" performance, but simply finding the highest quality memory I can afford. ^_^

The only reason I pay a premium for low latency, high speed, low voltage memory is...
Quality and quality alone.

1.5v is the JEDEC DDR3 voltage standard.
Stay with 1.5v or less if you can afford it..

What he said.

 

[Revolution 11]

Blain, I can agree with everything you said except for your 4th point of limiting purchases to G.Skill, Mushkin, etc. If the RAM can fulfill the first 3 points, does it really matter who makes the RAM?

 

[ShintaiDK]

Never buy 1.65V memory. Its overvoltage and out of spec. The same product failed at 1.5V.

 

[blastingcap]

What he said.

Except for certain applications, CAS latency has little effect. Even additional clock speed doesn't have that much effect, either, in most applications, once you hit DDR3-1333. http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/8

All bets are off if you are using an APU though. You want FAST FAST FAST RAM for APUs.

Agree on 1.5v or less for Intel CPUs. The 45nm AMD CPUs can tolerate 1.65v but I would still go 1.5v if it isn't much more expensive. Or get 1.65v RAM and undervolt it to 1.5v and downclock it as well.

Disagree on your ridiculously small number of brands, some of which don't even make their own RAM, e.g., my Kingston RAM is actually made by Hynix. I am running Ballistix 16GB on four DIMMs just fine. Samsung and Micron (Crucial) are tops in my book, but my experiences with G.Skill and Kingston have been good as well. Mushkin, Corsair, and others have good reps too but I can't personally vouch for them.