Question Is this an issue. Mixed timings on RAM.

Poncke

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Mar 23, 2016
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Hi guys, is this an issue?

My PC is not running fast and I cannot figure out why not. I noticed there is a difference in the RAM modules.

Is that an issue?

This is my set up


CPUID CPU Name Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
Motherboard Name MSI Z170-A Pro (MS-7971) (4 PCI-E x1, 2 PCI-E x16, 1 M.2, 4 DDR4 DIMM, Audio, Video, Gigabit LAN)
Motherboard Chipset Intel Sunrise Point Z170, Intel Skylake-S
Memory Timings 15-15-15-36 (CL-RCD-RP-RAS)
Command Rate (CR) 2T
DIMM1: G Skill RipjawsV F4-3000C15-8GVRB 8 GB DDR4-3000 DDR4 SDRAM (15-16-16-35 @ 1501 MHz)
DIMM2: G Skill RipjawsV F4-3000C15-8GVR 8 GB DDR4-3000 DDR4 SDRAM (15-15-15-35 @ 1501 MHz)
DIMM3: G Skill RipjawsV F4-3000C15-8GVRB 8 GB DDR4-3000 DDR4 SDRAM (15-16-16-35 @ 1501 MHz)
DIMM4: G Skill RipjawsV F4-3000C15-8GVRB 8 GB DDR4-3000 DDR4 SDRAM (15-16-16-35 @ 1501 MHz)
 

RealBeast

Titan
Moderator
All sticks should be set to run at the timings of the slowest stick.

Then run the free version of memtest86 for 3-4 passes with zero errors to insure that it is running properly. It is always best to buy all of your memory in sets, as that is how they are tested and guaranteed.
 
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Poncke

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I bought them in sets, thats why I was so surprised when I saw this. I bought one set 5 years ago and then the same set from the same supplier 3 years ago. So how that mismatch came about is a mystery.

How do I set the timings per stick? In the BIOS?

Also, I will contact the supplier to see if they can get me the correct matching stick.

What can happen if the sticks are not set up all the same?
 
My PC is not running fast
What does that mean? How exactly it is "not running fast"?

How do I set the timings per stick? In the BIOS?
You don't. It doesn't work that way. It's possible to set different timings per dimm channel (in your system you have 2 dimm modules per dimm channel). But it's better, if all channels have same settings.

Can you show screenshot from CPU-Z - memory section?
(upload to imgur.com and post link)
 
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Poncke

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Its not fast in the sense that apps are running slow. Lightroom 6.14 is slow as feck, almost unworkable. It used to be fast. Office 365 apps are slow to respond as well. In Word and Excel when I use right click mouse to pull up the options menu it lags, sometimes so bad I need to restart my PC. I have FastStone screen grabber, when I click Draw it lags to load the draw screen. It all used to be instant.

I am running Diskeeper, CC Cleaner and Bitdefender to keep my PC optimised. It used to be fast as hell now it just seems to have degraded. I think it might have something to do with a W10 update, but I am not sure. So I am trying all sorts of things and then I noticed the difference in memory timings.

I just completed running MemTest86, it took a little over 6 hours, zero errors.
 

Poncke

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I just read that it won't work because those memory kits (the original 16GB & the newer 16GB) are different, or at least one is 15-15 & the others are 16-16, so they are not the same RAM type. Thats what my OP was about. XMP apparently only works with the same RAM kits. I tried manually to set the frequency to 3000 but that failed also.

And why set timings to 15-16-16-35, when one stick is 15-15-15-35 ? Shouldnt the timing be set at the lowest?

Thanks again
 

Poncke

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No. Timings should be set to highest values.
Those are latency values. Higher numbers mean lower performance.
Right makes sense and that is what I meant. Its like in photography, where in aperture the higher the number the smaller the lens opening is. :)

Anyway, I have emailed the supplier to see if they can sort me out, because I ordered a dual kit but the modules are not identical.

I will make some changes to the BIOS to make sure it has the highest values (16). Because I think it is set at the lower value now (15).

Thanks. I will upvote your posts for the time you spent helping me.
 

RealBeast

Titan
Moderator
You don't need XMP to set memory values when you mix sets, just set them to the highest voltage, and slowest timings of any of the sticks manually in the bios. Then try increasing the speed incrementally until they are unstable, then back off the speed. Retest with memtest86.

And two separate sets are NOT a matched set of four ever. If you have issues contact G.Skill and they may swap your sticks out for a matched set of four, which they occasionally will do.

If
 

Poncke

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I have purchased a new set of RAM and now I have 4 identical RAM modules. It solved the issue with XMP, which is now enabled. I updated my BIOS to the latest version and I also enabled OC Genie 4.

It seems the PC is purring like a kitten now.
 

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