2133mhz DDR3 with Haswell

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MicahAlford

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Aug 19, 2014
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I am putting the final touches on the PC build I will be purchasing soon. I plan to run an i7 4790k on a Asus Z97-A mobo. I selected 2133mhz DDR3 (2x8) 16gb as my RAM, but on pcpartpicker.com, I receive a warning concerning the compatibility of my RAM at 1.65V with Haswell:

The G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-2133 Memory operating voltage of 1.6V exceeds the Intel Haswell Refresh CPU recommended maximum of 1.5V+5% (1.575V). This memory module may run at a reduced clock rate to meet the 1.5V voltage recommendation, or may require running at a voltage greater than the Intel recommended maximum.

Is this something I should be concerned with? Should I back off the 2133mhz to 1600mhz with 1.5V?
If 2133mhz is safe to use, is 2400mhz a good option as well? I believe the 2400mhz DIMMs are actually cheaper.

Here is my current build setup, which will be used for gaming, live broadcasting, etc:

http://pcpartpicker.com/user/MicahAlford/saved/DJPQzy

Thanks!
 
Solution
wildfire707
The warning is to let you know that the motherboard will not automatically increase the voltage to that level. If you want to run it at the rated speed, you will have to go into the BIOS and manually set the voltage higher and tell it to use the XMP (extreme memory profile) settings or manually enter the memory settings.

If you get memory that can run at the speed you want but does not need to be set to a higher voltage than 1.5, the XMP setting is normally used automatically on Z series chipset motherboards.

However, as several of the other people have pointed out here - higher memory speeds make very little difference to the performance of a computer. This is because of many factors, including that the CAS latency increases as you...
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That doesn't really answer my questions, though.
 
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Is this something you should be concerned with? Yes. You should keep things into spec.

Do you want DDR3-2133. get those instead:

PCPartPicker part list / Price breakdown by merchant

Memory: Avexir Core series 8GB (2 x 4GB) DDR3-2133 Memory ($75.99 @ Newegg)
Total: $75.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-20 05:43 EDT-0400

This is a great option:

PCPartPicker part list / Price breakdown by merchant

Memory: Corsair Vengeance 16GB (2 x 8GB) DDR3-2133 Memory ($174.99 @ Amazon)
Total: $174.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-20 05:51 EDT-0400
 
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If the memory excedes the voltage recommended for that CPU,then you either need to reduce the RAM voltage in the BIOS manually or the motherboard will automatically do it.
Press the power button on your PC to start.When you hear that beeping sound,start spamming the delete,F1 and F2 to access the BIOS.Then you need to find the RAM voltage.It's either in the CPU settings or the mobo settings.If it says 1.6V,then manually reduce it to 1.5V.
If it says 1.5V when you first check it,then just leave it.The motherboard has done it's job. :)
Hope this helps..now. 😉
 
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It seems as if everyone has a different opinion on this, and my research has shown the same. While one person says Haswell can handle 1.65V, others say it's a concern and should be avoided.
 
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You don't have to avoid it,you just need to reduce the voltage to 1.5 or 1.575V.You will also reduce the memory clock speed,but that really doesn't matter.1600 MHz is no different in terms of speed than 2400 MHz RAM. 😉
 
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The warning is to let you know that the motherboard will not automatically increase the voltage to that level. If you want to run it at the rated speed, you will have to go into the BIOS and manually set the voltage higher and tell it to use the XMP (extreme memory profile) settings or manually enter the memory settings.

If you get memory that can run at the speed you want but does not need to be set to a higher voltage than 1.5, the XMP setting is normally used automatically on Z series chipset motherboards.

However, as several of the other people have pointed out here - higher memory speeds make very little difference to the performance of a computer. This is because of many factors, including that the CAS latency increases as you ramp up the speed of the memory. So the memory can talk faster, but it takes longer to respond.

Your simplest solution is to use 1.5 volt memory at DDR3 1866 or DDR3 2133. A DDR3 1866 set like the G.Skill Ripjaws Z ( F3-1866C9D-16GZH ) runs at 1866 Mhz with CAS 9 latency. A DDR3 2133 set like the G.Skill Ripjaws Z ( F3-2133C11D-16GZL ) runs at 2133 Mhz with CAS 11 latency. Both work well and usually run at full speed without even entering the BIOS.

You will note that if you select either one of these kits at PC Part Picker, you will not get any warnings (just look for the Ripjaws Z kits with 1.4 to 1.5 volts, 16GB (2x8GB), and G.Skill selected).
 
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Solution


Have you even looked up (google) that part number from Avexir to make sure it will run at 1.5V@2133MHz? I did and show that it is the same like every else memory within this bandwidth: it will need to be set to 1.65V to be able run at its rated setting of 2133 MHz and latency of 11-11-11-31.

Here is Avexir specification: http://www.avexir.com/product/corespec.html
(SKU: AVD3U21331104G-2CI - use search within browser.)

From my understanding there is a need on Haswell system to set Volt higher if you want to be able to use higher bandwidth, then JEDEC standard of 1333 MHz and 1600 MHz which is what most main board is designed to work out of the box with memory and the IMC on CPU. That is why XMP profiles is being used to make it simpler for people that are not very comfortable to change setting in BIOS/UEFI to be able to use memory with higher bandwidth, then JEDEC standard.

There are plenty of sites that have the wrong information about setting for RAM incl ho much Volt that will be needed to run at a selected bandwidth, so it always best to go to the source of information (the producer or vendor of that RAM you want to buy). They should at least be able to provide the correct information for what they produce or sell in their own stores!


To the OP:

Almost all 2133MHz or faster will need 1.65 V to work at their rated bandwidth. In most cases you will need to go into BIOS/UEFI to check that your memory have been detected på the SPD and set to either JEDEC or XMP profile (when in automatic mode). You can set those setting by yourself if turn off auto detect and set it manual. I suggest you look up your manual for your main board on Internet (you will often find these things on "support" for your model). Make sure you also have the latest BIOS version running from the same page.
 
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I have an i7 4770k with 4.5 oc. I have G.skill Trident 2400 memory - specified at 1.65v. It's ran fine at 1.65v for DRAM voltage for several days. I incrementally reduced voltage to 1.585v which is what I keep it at now; still at 2400 memory clock.

If I had it to do over I'd probably get 1866 CAS 8 memory; at the time I got the 2400 at a much better price than the 1866 RAM.

PS - I did try running at 1600/1.5v but wasn't able to increase a stable oc over 4.5 (using Aida64 for stress testing).
 
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!.5 is the suggested voltage for sticks at 1600 with the CPU at stock...1.65 is perfectly safe (however I don't recommend it for plain jane 1600 or 1866 sticks, if they need more tha 1.5-1.55 it's just indicative of weak memory ICs, 2133 and up - 1.6 - 1.65 is the norm and safe...Intel even Certifies 1.65 DRAM so yes it's safe 😉
 
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With 2133 or 2400 DIMMs would I have to set the voltage in BIOS to 1.5? Or 1.65?
 
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