AMD Zen 2 Memory Performance Scaling with Ryzen 9 3900X

[W1zzard]

We take a close look at memory scaling on AMD's new Zen 2 Ryzen 3900X, testing both application and gaming performance at seven different memory speed and timing combinations ranging from 2400 MHz all the way up to 4000 MHz.

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[TheLostSwede]

So glad I got that 3600 RAM, it looks like it's the sweet spot to be at.

 

[Metroid]

Thanks for the review, the only way I guess to test the 3733mhz is xmp profile. As we can see memory wise 3600 is the best, however the difference is less than i thought it would be, close to 5%, from bottom to top and most of the times at 2% from bottom to top, so best thing is dont waste your money getting a better memory with tighter timings, lax the timings and put it at 3600 or at the best highest possible speed but make sure lower than or equal 3733mhz.

 

[Zubasa]

Thanks for the review, the only way I guess to test the 3733mhz is xmp profile. As we can see memory wise 3600 is the best, however the difference is less than i thought it would be, close to 5%, from bottom to top and most of the times at 2% from bottom to top, so best thing is dont waste your money getting a better memory with tighter timings, lax the timings and put it at 3600 or at the best highest possible speed but make sure lower than or equal 3733mhz.

It is what I expect with the doubling of L3 cache on Zen2, bigger caches hides memory latency better and thus less reliant on ram speed.

 

[W1zzard]

Thanks for the review, the only way I guess to test the 3733mhz is xmp profile

Not gonna happen, at least on my CPU, unless you reduce the sped of Infinity Fabric, which kinda defeats the point of 3733 in the first place

 

[Metroid]

Not gonna happen, at least on my CPU, unless you reduce the sped of Infinity Fabric, which kinda defeats the point of 3733 in the first place

So you think that even with xmp profile it will not work? So we will never have a 3733mhz memory linked 1:1 to infinity fabric as lisa stated?

 

[jesdals]

Nice test and good to know when considering a new build

 

[W1zzard]

So you think that even with xmp profile it will not work? So we will never have a 3733mhz memory linked 1:1 to infinity fabric as lisa stated?

Definitely not on my cpu sample, I tried. 1800 is max IF on it

 

[Metroid]

Definitely not on my cpu sample, I tried. 1800 is max IF on it

Ah okay, thanks, it might have at the moment probably to be an issue somehow, maybe a motherboard bios update might fix that. Thanks very much for the review, very concise.

 

[Mirkoskji]

So basically, if you're not interested that much on having the 3 fps boost, you could potentially buy a ddr4 3000 or 2933, spending something less, and still have pretty good performance? is it right?

 

[_UV_]

That is really nice, i can grab pair of used 8GB 2400 RAM as a starter kit for X570 and 3950X, and buy higher speed more density a bit later. Finally time to upgrade my main rig to get 3-8x performance.

 

[junglist724]

That's some really high latency DDR4-4000

 

[TheGuruStud]

3600 CL16 is going to be the sweet spot. It's dirt cheap. Buy some C/E die 3200 and OC. I got 32GB for $126.

 

[TheLostSwede]

Definitely not on my cpu sample, I tried. 1800 is max IF on it

This is not directly CPU related, apparently, at least for the time being, most of the board makers have limited their boards to DDR4 3600, as DDR4 3733 is unstable and they seemingly didn't want to chance it. It might appear over time, but it depends on AGESA improvements from AMD I guess.

 

[windwhirl]

Well, for me the most important thing from this is that I don't have to worry about cherry-picking memory kits. That's a freaking nightmare here (etailers here sometimes don't specify the exact model they're selling, or sometimes you buy a memory kit that should be XX1234 and ends up being XX1233 or XX1235 or something). And I don't feel like going with a QVL list to a brick-and-mortar store.

Thanks TPU for all the reviews released today and specifically for this one, which had me worried more than anything else.

 

[bug]

That low memory hit in single channel might be a bonus for mobile parts. Often the cheaper laptops come with a single DIMM of memory.

 

[B-Real]

Thank you W1zzard for the diversified tests. You made an X470-X570 comparison, a PCI-E 4.0 - 3.0 - 2.0 comparison and memory speed comparison. Great work, really.

 

[bug]

Thank you for the diversified tests. You made an X470-X570 comparison, a PCI-E 4.0 - 3.0 - 2.0 comparison and memory speed comparison. Great work, really.

@W1zzard has already said this has been the busiest week at TPU since forever. He wasn't lying

 

[Zubasa]

So basically, if you're not interested that much on having the 3 fps boost, you could potentially buy a ddr4 3000 or 2933, spending something less, and still have pretty good performance? is it right?

That really depends on the pricing you get, now a days it is often about the same price for DDR4 3200 CL16 vs 3000.
Even DDR4 3600 CL17 is not really that much more in many cases.
DDR4 3200 CL14 is often the more expensive kits.

 

[W1zzard]

@W1zzard has already said this has been the busiest week at TPU since forever. He wasn't lying

There's 6 more reviews coming for nvidia super, soon

 

[Tomgang]

So based on this, it looks like Ryzen 3000 likes low timmings on memory maybe more than high memory clock. 3600 MHz seems to give the best price vs. performance gain and then just get two dims rated for 3600 MHz and find the pair of dimms that has the lowest timmings possible or you cut maybe find dimms with higher memory clock rating, but still set them to 3600 MHz and then press timmings even lower as that shut be possible then.

So if i get ryzen 3000. I will either chose 3600 MHz rated dimms with the lowest timmings ratings or get a pair that has high memory clock ratting and still set them to 3600 MHz and press timmings from there as low as possible.

 

[A.Stables]

"We did run into some problems when playing with the settings, though. The latest BIOS of our ASRock X570 Taichi motherboard has a strange bug that overrides your CAS latency input sometimes. For example, CL17 could simply not be set, and it would instead apply 18T—the same happened in Ryzen Master. "

Gear down setting in bios? Zen likes division of 2. 14, 16, 18 etc

 

[bug]

There's 6 more reviews coming for nvidia super, soon

And there I was thinking you guys were slacking off

 

[shmuck]

So basically virtually imperceptible FPS gains for higher bandwidth RAMs at higher resolutions? I was thinking of getting a pair of 3600 CL17 at first, but I reckon 3200 CL16 for ~60% of the price will be more than enough.

 

[W1zzard]

So basically virtually imperceptible FPS gains for higher bandwidth RAMs at higher resolutions? I was thinking of getting a pair of 3600 CL17 at first, but I reckon 3200 CL16 for ~60% of the price will be more than enough.

Yup, and the latency matters too