P6T Deluxe (X58) - do these DIMMs mix?

[FlippedBit]

Greetings,

I've got this currently:
6GB (3x2GB) OCZ3G1600LV2G. These are stamped 8-8-8-24@1.65V. I'm attaching screenshots from CPU-Z of their actual timings on my computer.

I've got this kit on order:
12GB (3x4GB) G.Skill F3-12800CL9T-12GBRL. These are stamped 9-9-9-24@1.5V.

My expectation is that they are not compatible and I will not be able to combine them for a total 18GB. I am expecting to just replace my 6GB kit with the 12GB.

However, if I'm mistaken, and I can actually use both together... I would love to know! I don't want to just try it and risk frying something out of ignorance.

Overclocking is not a consideration; just stability, and to the extent possible, performance.

For what it's worth I'm pasting the relevant info from the motherboard manual, but I recognize that at least some of the information there may be out of date or more of a recommendation than a hard rule.

You may install 1GB and 2GB unbuffered and non-ECC DDR3 DIMMs into the DIMM sockets.

• You may install varying memory sizes in Channel A, Channel B, and Channel C. The system maps the total size of the lower-sized channel for the dual-channel or triple-channel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation.
• Due to Intel spec definition, X.M.P DIMMs and DDR3-1600 are supported for one DIMM per channel only.
• According to Intel CPU spec, DIMMS with voltage requirement over 1.65V may damage the CPU permanently. We recommend you install the DIMMs with the voltage requirement below 1.65V

I'm not sure how to interpret and apply this to what I'm looking to do, and am ignorant about memory interoperability, JEDEC specs, etc.

Thanks in advance!

 

[BonzaiDuck]

I don't advise mixing RAM of different manufacture, although some here have, on occasion, proven that it can be done to work.

If you really want to pursue this tack, make a note of the JEDEC and XMP timings, speeds and voltages with CPU_Z, and see if the two different types of RAM overlap and coincide at this or that speed.

 

[rchunter]

I'm running x58 platform (p6x58d premium) and run mixed speed ram and i'm still overclocking just fine (not the ram). I have my ram speed set at 1600mhz.
Just set your spd timings to that of the lowest stick. It might or might not work for you depending on how picky your motherboard is.

 

[nenforcer]

Yeah it's generally advised to not mix RAM of different voltages (or even CAS timings) but you can try setting all of the sticks manually at 9-9-9-24 @ 1.65V and see if its stable.

 

[PhIlLy ChEeSe]

Cancel your order or just buy more of the same, general rule is not to mix and match.

 

[FlippedBit]

Thanks, I'll mess around a bit when it arrives (should be here in time for the weekend) but if it's not showing promise I'm just going with the 12GB kit. I calculated that 12GB is all I really need, anyway for Windows + a Linux VM.

These triple-channel kits are becoming so rare and expensive, and I don't want to gamble on eBay. NewEgg had a 12GB matched kit, or a 24GB kit... and I didn't want to spend $220 on the 24GB kit. Rather put the additional money toward the next PC down the line.

 

[Burpo]

I just got brand new Kingston DDR3 1066 12Gb kit off ebay for $37 delivered (ECC). Testing on X58 with Xeon soon..

 

[FlippedBit]

Good luck, that's a steal! I'm stuck using this "Gaming" roll-of-the-dice consumer crap

Will *definitely* look hard at ECC RAM if I ever get to build my dream NAS / video server...

 

[FlippedBit]

Hey all, I got the new RAM today. Good news, and bad. Hopefully someone can explain the voltage issue.

The good news: system boots with ALL sticks installed (18GB, mixed modules). It doesn't matter whether I set XMP on or off, or whether I select DDR-1066, -1333 or -1600. They all boot and Windows sees all 18GB.

The bad news: The new RAM from G.Skill seems to want to run at 1.7V no matter what I do. I even pulled out the OCZ sticks leaving just the 12GB G.Skill kit. I tried all the different O.C. settings in the BIOS (XMP, "Auto", "Manual") and even manually set DDR-1066 through DDR-1600. In all cases, the DRAM voltage stays at 1.7V. The sticks are rated at 1.5V. What gives??

 

[rchunter]

Yeah, disable xmp. There's got to be a place that you can manually set voltage. Look for a place in your bios that says dram voltage and manually type it in. Go into spd settings and manually type in the ram timings for your slowest 3 sticks of ram. Set your ram speed to 1600mhz and look in cpuz and make sure it's running in triple channel mode.
After all that's done you're going to want to run memtest for at least a few hours to make sure everything's good.

 

[FlippedBit]

I set timings and voltage manually, and everything seems stable, but there's still something I don't understand regarding the voltage readout. I'm thinking that there's something specific about my motherboard or chipset that I'm not aware of.

Again, Asus P6T Deluxe (X58) with stock Intel Core i7-920 (Nehalem). I've set all 6 sticks to DDR3-1600 9-9-9-24 @ 1.5V. I guess this means the OCZ sticks are undervolted, as they are rated for 1.65V, but they are playing nicely so far.

You can see where I've specified 1.5V for the DRAM bus.

My QPI / NB link has been automatically clocked to 3.2GHZ (from the stock 2.4GHz), but it seems stable. Here's the result from memtest for a little over 7 hours:

Now the part I'm not understanding...

The DRAM voltage readout in HWMonitor is still 1.7V.

Am I looking at the wrong voltage?
Is this something unique about my particular motherboard?
Is there a different app that I need to use in order to see the correct voltage?

I couldn't find any readout of the RAM voltage in the BIOS itself. There's only +3/+5/+12VCC and CPU core voltage I think.

Also, I verified that the readout is still 1.7V even with my original RAM configuration of just the 3x2GB OCZ sticks. I was wrong about this being specific to the G.Skill kit.

 

[rchunter]

I wouldn't worry about it too much. You can adjust it down a bit if you want though. Many motherboards will overvolt the ram a bit. I'd recommend downloading prime 95 and run the Blend test which tests both CPU and ram. I think you're good to go though.

I'm running 18 GB of mixed memory on my x58 but the only thing different is the timings, Both of my kits are 1.65v.

 

[FlippedBit]

Got prime 95 running in the background now... let's see

Thanks for the help.

Still seems odd that the RAM voltage will never budge from 1.7V, even with just 1.5V rated modules installed. What's the point of being able to specify a voltage if it's just going to use 1.7 no matter what?

 

[rchunter]

Got prime 95 running in the background now... let's see

Thanks for the help.

Still seems odd that the RAM voltage will never budge from 1.7V, even with just 1.5V rated modules installed. What's the point of being able to specify a voltage if it's just going to use 1.7 no matter what?

Just to let you know QPI/DRAM Core Voltage needs to stay within 0.5v over/under the DRAM Voltage. I have my dram volts set at 1.65 and I have my QPI/dram core voltage at 1.30v.
As to why yours is stuck and you can't adjust dram volts I don't know. Maybe someone else more knowledgeable has an answer.

 

[FlippedBit]

Ran Prime95 torture test for >24 hours... 0 errors. I'm happy to call this project "done"




Unfortunately I have no way to read the QPI/DRAM Core voltage as my motherboard doesn't give voltage readouts in the BIOS, and that one doesn't appear in any of the monitoring apps that I have. I've left that particular voltage set to "Auto" in the BIOS and am trusting the computer to handle it appropriately.

Now to rock some VirtualBox VM's...

 

[rchunter]

Good to hear. Your 1.7 dram voltage reading probably isn't even correct anyway. To tell you the truth I looked and I can't get a reliable dram voltage reading either. Mine is reading 1.5v in some programs and 1.8v in others, when I have it set at 1.65v. I don't worry about it. I have it set at 1.65v with a 1.30v qpi bus voltage.