Mixing RAM modules with different CAS timings?

[joanne firus]

Hey all.

My rig currently has 4x8GB Mushkin Blackline Frostbyte (1600Mhz, PC3-12800, 9-9-9-24).

I'm looking to max out the RAM by adding another 16GB;
and I've found a set of Corsair XMS3 2x8GB (1600Mhz, PC3-12800, 11-11-11-30) for cheap.

Question is: will it play nice with the RAM that I currently have?

 

[joanne firus]

Bump

 

[ZeroRift]

I wouldn't try to mix memory, personally. I never have simply because, best case, your nicer sticks will be stuck running at the speed of the slower ones (At least, that's my understanding).

To address your question: It will probably work as long as your BIOS can find a set of timing that both sets will agree on (most likely 11-11-11-30). If your BIOS can't figure it out, you may be left to enter the timings manually to get them to work and even then you may be SOL. This is also assuming the sticks are rated for the same voltage....

Perhaps someone who's tried this will be able to chime in?

 

[Charles Kozierok]

Haven't tried this combination, but modern motherboards are generally smart enough to figure this stuff out.

 

[joanne firus]

Well, the Mushkin sticks are rated at 1.6V whereas the Corsair sticks are at 1.5V...so yea, they have different voltage ratings AND CAS timings.

 

[bononos]

Your mobo would probably have to run the sticks at 1.6v and 11-11-11 at at ddr3 1600 speed.

You could try manually lowering the speed to ddr3 1333 to drop the voltage and latency.

 

[Joseph F]

If you have a SB or IVB CPU, you shouldn't run the RAM at voltages higher than 1.55V.

 

[chimaxi83]

If you have a SB or IVB CPU, you shouldn't run the RAM at voltages higher than 1.55V.

Where'd that number come from?

 

[joanne firus]

My system is an i7 960, on an Asus P6X58-E Pro mobo.

 

[Joseph F]

Where'd that number come from?

Intel. Just ask the rep who comes around here now and then.

Err, I was wrong. It's 1.575V:
http://www.intel.com/content/www/us/en/processors/core/2nd-gen-core-desktop-vol-1-datasheet.html
Page 82

 

[Ben90]

Well, the Mushkin sticks are rated at 1.6V whereas the Corsair sticks are at 1.5V...so yea, they have different voltage ratings AND CAS timings.

JEDEC's got us covered
Even 1.9V DDR3 is going to boot automatically at 1.5V until someone changes it.