Zen2 and 2x16 or 4x8?

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Hey everyone! I bought almost everything today to finally upgrade from my old 2600K build, the only thing that I'm missing is ram. I've been looking and looking... and looking... and I keep changing my mind but I guess that's somewhat to be expected with a new cpu and chipset. But back to the original question, from what I've read it sounds like I could take a performance hit when getting 4 ram sticks over 2? I haven't settled on ram yet but I'd like to have 32GB of 3600-CL16. I've honestly been looking at getting 4 sticks over 2 for aesthetics.

Here's the Asus supported ram listing (for Hero VIII) and a Trident Z Neo kit that I am considering. It says it has 4 dimm support for this kit but I honestly don't know what that means. I think I'm ok with a slight performance hit if I have to go 4 sticks I just don't want to cripple it.

Capture.PNG

Thanks for the support!

What I've bought so far:
R9-3900X
Crosshair VIII Hero
bunch of other stuff.
 
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Dan_D

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The problem is, going above 2933MHz with four sticks isn't supported by AMD. While some people have been able to do it successfully, many haven't and there are no guarantees that you can.
 
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Thanks man! And damn... lol. So essentially it's a risk that if I were to buy 4 sticks of 3600 I might not get that where 2 sticks it'd be a guarantee. I don't like to buy something, open it and try it if I know that there is a chance I might be returning it, but being that that Neo kit says it's Ryzen 3000 compatible I might risk it. I'd know upon boot when it shows the speeds if it was compatible right? I think the biggest question I have now is why include 4 ram slots if only 2 are going to be fully supported?

Thanks again, it's been far too long since I've built a system, lol.
 
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Dan_D

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Unfortunately, even if it boots at DDR4 3600MHz with four modules, that doesn't mean squat. You won't know until you actually get an OS on the box and do some stability testing that stresses the RAM. The modules are Ryzen 3000 series compatible, but that doesn't guarantee it will operate at full speed using four modules. The RAM makers can't guarantee that. They can't even come close to doing so as the motherboard and individual CPU IMC's make all the difference on that front.
 
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Unfortunately, even if it boots at DDR4 3600MHz with four modules, that doesn't mean squat. You won't know until you actually get an OS on the box and do some stability testing that stresses the RAM. The modules are Ryzen 3000 series compatible, but that doesn't guarantee it will operate at full speed using four modules. The RAM makers can't guarantee that. They can't even come close to doing so as the motherboard and individual CPU IMC's make all the difference on that front.
Well... damn man. I fully trust your opinions so maybe I'll just go 2x16. I'll be honest that I don't fully understand the purpose of supplying 4 dimm slots if only 2 are going to be guaranteed to work out of the gate. Maybe they'll make some prosthetic ram chips, lol.
 

Dan_D

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You can use four, but again AMD only supports speeds up to DDR4 2800MHz or 2933MHz depending on if its single or dual-ranked modules being used. Keep in mind that speeds over JEDEC specs are always technically through overclocking, which isn't guaranteed.
 
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Well this ram purchasing is turning out to be far more complicated than I had imagined.
 

Dan_D

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Have any suggestions?

This perhaps?
Unfortunately, my range of hardware recommendations are pretty narrow. Generally, I can say go for any mid-range board from the big three, or upper tier ASRock, but I can't speak from personal experience. I have only tested two X570 motherboards thus far. The MSI MEG X570 GODLIKE and the ASUS Crosshair VIII Hero. The former, was excellent after a BIOS update. The latter, is good thus far, but I can't get boost clocks to work right on it using the 3900X. I'm working with ASUS to resolve those issues.

I've heard great things about the GIGABYTE X570 Aorus Master, but again, that's just by reputation and me looking at images of it. For RAM, G.Skill's Trident Z series seems good. I've only tried the Trident Z Royal, which is good RAM, but UGLY as hell.
 
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Unfortunately, my range of hardware recommendations are pretty narrow. Generally, I can say go for any mid-range board from the big three, or upper tier ASRock, but I can't speak from personal experience. I have only tested two X570 motherboards thus far. The MSI MEG X570 GODLIKE and the ASUS Crosshair VIII Hero. The former, was excellent after a BIOS update. The latter, is good thus far, but I can't get boost clocks to work right on it using the 3900X. I'm working with ASUS to resolve those issues.

I've heard great things about the GIGABYTE X570 Aorus Master, but again, that's just by reputation and me looking at images of it. For RAM, G.Skill's Trident Z series seems good. I've only tried the Trident Z Royal, which is good RAM, but UGLY as hell.
Lol, I agree on the royal.

I've got a 3900X, Crosshair VIII Hero, psu etc getting delivered tomorrow or Thurs. So I've got to get moving on the ram. I like the timings of that Trident Z Neo 3600@16-16-16-36 (b-die) but I'm not having any luck finding it in stock. Maybe I'll just grab a single $20 stick of ddr4-3000 just to make sure everything boots while waiting for the Neo to come back in stock.
 

Dan_D

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I like the Crosshair VIII Hero so far, but still working out the boost clock stuff.
 
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Riccochet

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It appears these 3000 series CPU's are a lot more lenient when it comes to RAM make/model/speed/layout than previous gen Ryzen. At least from the couple people I know that built Zen2 rigs. None, including myself, have used "Ryzen specific" or even QVL listed RAM in our rigs. In fact the TridentZ 3600 in my rig has an Intel label on the box it came in, an no mention of AMD anywhere. It's not on the QVL and I'm running it in 4x8 config with respectable timings.

I don't feel the Ryzen labeled RAM is worth the extra money.
 
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I ended up getting Trident Z Neo 4x8GB 3600 CL16 B-die. I went 4x8 instead of 2x16 for appearance honestly. I've got it up and running, set xmp profile to 3(oc) and according to cpu-z it is running at 3600. I need to stress it to see if it's running stable. I'll give prime95 and memtest a shot, any other stressor I should be looking at?
 

Bloax

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Pardon the double post, but this forum isn't lively enough to check for people doing minor addendums to their posts. ; )

One thing to bear in mind is that going above 1.325v vCore while doing CCX or all-core (the former yields better results), you can and will degrade your chip with surprising speed.
My 3600 used to be able to hold 1866 fCLK (3733 memory), but now after some proper abuse - between AutoOC+50 with a +0.05v offset and 4.2 Ghz allcore @ 1.406v - it has now retired to 1833 (3666) with tighter subtimings after less than a month.

It was mentioned before somewhere, but I'm just going to remind you of this based on personal confirmation of this information. >;^)
 
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Pardon the double post, but this forum isn't lively enough to check for people doing minor addendums to their posts. ; )

One thing to bear in mind is that going above 1.325v vCore while doing CCX or all-core (the former yields better results), you can and will degrade your chip with surprising speed.
My 3600 used to be able to hold 1866 fCLK (3733 memory), but now after some proper abuse - between AutoOC+50 with a +0.05v offset and 4.2 Ghz allcore @ 1.406v - it has now retired to 1833 (3666) with tighter subtimings after less than a month.

It was mentioned before somewhere, but I'm just going to remind you of this based on personal confirmation of this information. >;^)
I appreciate the responses!

I'm not pushing the ram past what it's advertised speeds/voltages are, not to say that that won't cause degradation. I got memtesthelper running but am not sure how long to run it? I ran it to 500% so 5 passes? Without error. I ran memtest86 through 4 passes without error. I'm fine ramping up the fans and running memtest (memtesthelper) overnight if need be. Is there any kind of a base time for testing ram stability?
 

rat

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I appreciate the responses!

I'm not pushing the ram past what it's advertised speeds/voltages are, not to say that that won't cause degradation. I got memtesthelper running but am not sure how long to run it? I ran it to 500% so 5 passes? Without error. I ran memtest86 through 4 passes without error. I'm fine ramping up the fans and running memtest (memtesthelper) overnight if need be. Is there any kind of a base time for testing ram stability?
Not really. By the time you clear 3 passes, you've pretty much run it through the gamut. Any issues that would crop up after running the system for a few hours would have shown up by then.

Ryzen being strange about 2 vs 4 sticks and ram speed was why I ended up just getting a two slot mITX board. The benchmarks across all gens showed more scaling in performance when tied to ram speed, so it seemed smarter to just go for dual and highest speed possible over quad sticks.

I second what Ric said above, the price difference for AMD 'approved' ram didn't seem to be justified. I (ab)used my Amazon refund policy and grabbed the fastest ram I could reasonably justify on price (that made no mention of AMD or Ryzen) and my Ryzen 2 proc handled it just fine.
 

Bloax

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It's a good idea to buy RAM that's on your motherboard's QVL, if simply for the non-adjustable RAM settings being configured properly for them - as they can make quite the performance impact.

Ryzen Compatible is a funny thing leftover from Zen1 :- )
 
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