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FlorbFnarb

Is there something I'm not understanding about RAM frequencies?

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Could use some education from anybody who knows, especially @Folterknecht, because I'm super-confused.

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Recently moved from 16 GB to 32 GB, got this DDR4-2400 C14 from Corsair:  https://www.amazon.com/dp/B0134EU9YA?ref=ppx_yo2_dt_b_product_details&th=1\

This is what I had before: DDR4-2400 C16 https://pcpartpicker.com/product/c8rcCJ/geil-memory-gpr416gb2400c16dc

Now, this is what I'm seeing in BIOS: https://imgur.com/a/KR6GEnY

What I got was listed as DDR4-2400 C14 - there was C16 available, but I figured if all else is equal, why not pick up lower latency?

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However, I read up a bit on the Wikipedia page about DDR4 RAM: https://en.wikipedia.org/wiki/DDR4_SDRAM#JEDEC_standard_DDR4_module

It's telling me that DDR4-2400 is PC4-19200. and should run at a peak transfer rate of 19200 MB/s, and in fact the old RAM I have has a sticker labeling it as that very thing: https://imgur.com/a/j5TdOrb

However, if you note the second and third images in the first imgur link, it's telling me the stuff is running at a peak bandwidth of PC4-17000, or 1067 MHz, which at double data rate is basically 2133 MHz.

But I don't have DDR4-2133 - even the first page of the BIOS RAM analysis says 2400 MHz.  So WTF is going on?  What am I missing?

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DDR4 runs at 2133 MHz by default, no matter how fast your ram actually is. Have you enabled XMP? It should run at 2400 MHz then, like shown in one of your screenshots.

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Jul_Le is right. 2133 MHz is the JEDEC baseline for DDR4 for max compatibilty at the 1st start up. You 'll have to load the XMP1 Proffile +Save&Exit +Reboot to apply it. You can also check under Windows with CPU-Z (memory tab), if the corrrect profile is applied.

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Oh crap, so I have to *make* it run at 2400?  Christ, I never did that with the preceding RAM either.  Fucking hell.

Alright thanks guys, I'll check it when I get home.

I posted some screenshots of my BIOS readouts; do they look like it's running at 2400 or 2133?

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4 minutes ago, Folterknecht said:

Atm it looks like 2133 MHz.

Go into your BIOS, go to OC Tweaker -> DRAM Connfigurration -> Load XMP Setting + Save&Exit and check with CPUz like I said above.

Ok thanks.

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I'm also getting occasional BSODs, and I'm not sure why.  I already unplugged the whole damn thing, took the RAM sticks out, and reseated them from scratch.  Nothing else could really be the issue; I only changed the RAM.  I'm close to putting the old stuff back in to see if it persists.

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12 hours ago, Folterknecht said:

Atm it looks like 2133 MHz.

Go into your BIOS, go to OC Tweaker -> DRAM Connfigurration -> Load XMP Setting + Save&Exit and check with CPUz like I said above.

Looks like it worked:

 

 

 

4wfmN0j.png

6 hours ago, Folterknecht said:

Memtest your RAM over night, stick by stick outside of windows.

Will do.

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97000% tested, no errors.  Well, hopefully reconfiguring the RAM to 2400 resolved the BSOD issue, although I don't know why it would - but I haven't had a BSOD since I did it.

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@FlorbFnarb If everything runs well in the next week(s) and you want to gain a little performance, manually set your DRAM voltage to 1,35V, your CAS Lantency (CL) to 16 or 15 and your DRAM Freqency to 1500 (3000) MHz. The rest leave at it is.

Most DDR4 (even 16GB) DIMMs should be able to handle that nowdays without much fiddling around.

 

Leave your fingers off secondary or tertiary timings.

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16 minutes ago, Folterknecht said:

@FlorbFnarb If everything runs well in the next week(s) and you want to gain a little performance, manually set your DRAM voltage to 1,35V, your CAS Lantency (CL) to 16 or 15 and your DRAM Freqency to 1500 (3000) MHz. The rest leave at it is.

Most DDR4 (even 16GB) DIMMs should be able to handle that nowdays without much fiddling around.

 

Leave your fingers off secondary or tertiary timings.

Alright, I'll give it a shot.

Why would I want to set the latency to 16 instead of 14 though?  Is that required for the higher frequencies?  I know that RAM latency has risen along with frequency.

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13 minutes ago, FlorbFnarb said:

Why would I want to set the latency to 16 instead of 14 though?  Is that required for the higher frequencies?  I know that RAM latency has risen along with frequency.

There a many 8GB DIMMs that can do CL 14 (or lower) at 3000 MHz. With 16 GB DIMMs Its a different story, they usually don't clock nearly as well. Increasing Freq. by 25% is a big step (you can try 2666 MHz in between). CL16 @3000 MHz is pretty relaxed. CL14 in your case is marketing gag anyway, as the rest of the timings are loose anyway for that speed (2400 MHz).

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1 hour ago, Folterknecht said:

Forgtt something, if you system is stable atm, make a BIOS Update before you start messing around.

Will do.  Pretty sure I haven't done that since I put the thing together.

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