AMD Ryzen memory optimisation - The effect of tRC timings

Introduction

AMD Ryzen memory optimisation trick

Introduction

When AMD's new Ryzen platform launched, memory support was all over the place, with many DIMMs refusing to run at their rated speeds and some kits that simply refused to boot at all. 
 
Since then with the help of new BIOS/UEFI updates and the release of newer AMD AGESA microcode updates, things have improved tremendously, but that still does not mean that AMD's Ryzen platform is perfect in regards to memory support, especially when many new AGESA 1.0.0.6 BIOS versions are still in beta.

With the release of AGESA version 1.0.0.6 we promised to look deeper into the new options provided by the new update and through that search, we have found a neat little trick that will improve Ryzen's memory performance. Today we will be showing you not only how to test this new performance tweak yourself, but also have a look at the performance impact of this change in a wide range of scenarios. 

 

Rise of the Tomb Raider update - Has AMD Performance Ryzen?

 

tRC Memory Timings

In our initial Ryzen performance testing, we noticed a strange trait that was present on every AM4 motherboard that we tested so far. The motherboard always set the Bank Cycle Time (tRC) of our motherboard to 75 clocks, instead of the 48 clocks that were listed in the DIMMs XMP table. 

This oddity was present in every Ryzen motherboard that we have tested so far, making this a general Ryzen problem, but why is it there? Is it for stability reasons? Performance reasons? The biggest question we have is whether or not changing this timing to our memory's default XMP value will result in a noticeable performance boost. 

(We have heard reports that some recent ASRock BIOS files utilise XMP rated tRC Timings) 

 

AMD Ryzen memory optimisation trick

 

Test Hardware

We will be conducting our performance testing using ASUS' Crosshair VI Hero motherboard alongside AMD's Ryzen 7 1700X CPU. Here we will be using G.Skill's 3200MHz DDR4 memory on this test bed and use the same timings of 14-14-14-34 on ASUS' AGESA 1.0.0.6 BIOS releases (BIOS version 1403).  

In this test, we will be using our Ryzen 7 1700X with a 4GHz overclock, effectively showcasing how this tweak can improve performance on a "pre-tweaked" Ryzen system. We will also look at how this tweak affects 2666MHz and 3200MHz memory speeds. 

 

AMD Ryzen Game Test Rig
AMD Ryzen 7 1700X @ 4.0GHz
ASUS X370 Crosshair VI Hero
G.Skill Trident-Z 2x8GB DDR4 3200MHz
Corsair 460X System Chassis
Corsair RMi650
Corsair H115i
Nvidia GTX 1080 Founders Edition
Windows 10 x64 "Creators Update"

 

Rise of the Tomb Raider update - Has AMD Performance Ryzen?

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Most Recent Comments

18-07-2017, 13:59:45

Chrazey
I like it how the test rig specs in the box say "1080 Founders Edition", although the picture of the PC under it shows and ASUS Strix card Quote

18-07-2017, 14:02:05

WYP
Quote:
Originally Posted by Chrazey View Post
I like it how the test rig specs in the box say "1080 Founders Edition", although the picture of the PC under it shows and ASUS Strix card
That is the thing with test beds, hardware changes all the time. I can't take pics with every hardware configuration.Quote

18-07-2017, 14:08:58

Chrazey
Quote:
Originally Posted by WYP View Post
That is the thing with test beds, hardware changes all the time. I can't take pics with every hardware configuration.
No no, I understand dude. I was just pointing it out, not to put it in your face or anything though.Quote

18-07-2017, 16:49:54

harrison
For whatever it's worth, my memory/motherboard does not seem to exhibit this issue. My XMP 2.0 values populated and booted without any fussing, and the tCR value is accurate.

MB: ASRock AB350M Pro4, BIOS v2.5 (AGESA 1.0.0.6)
Ram: Corsair LPX 2x8GB 3200MHz C16 (CMK16GX4M2C3200C16S)
Timings: 16-18-18-36-54-1 (tCAS-tRC-tRP-tRAS-tCS-tCR)
https://valid.x86.fr/te3x7z

A new update was just released today for AGESA 1.0.0.6a, so I'll need to see how that impacts things, but in this one case at least, things appear to not wonky.Quote

18-07-2017, 17:12:14

WYP
Quote:
Originally Posted by harrison View Post
For whatever it's worth, my memory/motherboard does not seem to exhibit this issue. My XMP 2.0 values populated and booted without any fussing, and the tCR value is accurate.

MB: ASRock AB350M Pro4, BIOS v2.5 (AGESA 1.0.0.6)
Ram: Corsair LPX 2x8GB 3200MHz C16 (CMK16GX4M2C3200C16S)
Timings: 16-18-18-36-54-1 (tCAS-tRC-tRP-tRAS-tCS-tCR)
https://valid.x86.fr/te3x7z

A new update was just released today for AGESA 1.0.0.6a, so I'll need to see how that impacts things, but in this one case at least, things appear to not wonky.
Well that is certainly a positive thing to hear, one of the main points for this is to raise awareness and get a potential fix in future BIOS' if possible. I do remember the Taichi having the issue at launch, so this is likely a recent development.

Hopefully other manufacturers will soon follow suit. It is memory performance that is simply sitting on the table.Quote
Reply
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