DDR4 Memory Scaling on AMD AM4 Platform – The Best Memory Kit For AMD Ryzen CPUs

By Nathan Kirsch

Conclusion – What Is The DDR4 Sweet Spot For Ryzen

AMD Ryzen 7 1700 With ATI Ruby
AMD Ryzen 7 1700 With ATI Ruby

After using the AMD Ryzen 7 processors for almost two weeks no on the MSI X370 XPower Gaming Titanium motherboard we’ve found that this processor loves all the memory bandwidth that it can get. The good news is that DDR4 memory pricing is actually pretty reasonable right now and there isn’t much of a price difference between a 2133 MHz memory kit and a 3200 MHz memory kit as all the high-cost DDR4 memory kits are now over 4000 MHz. By going to 3200 MHz over 2133 MHz we were seeing near 50% performance improvement in simple memory bandwidth tests and a 16% performance jump in our 1080P gaming test. Hopefully AMD board markers will update their UEFI builds to allow for higher than 3200MHz memory kit use without needing to mess with the adjusting the bus speed of the processor (RefClck).

Here is a quick look at the memory read performance on AIDA 64 versus the price you pay for a Corsair Vengeance LPX DDR4 16GB memory kit (first five listed below). As you can see the MB/s cost per dollar spent goes up nicely, so no you have a cost reason to go faster!

Corsair Vengenance LPX 16GB DDR4 Memory Kits 2133MHz to 3200MHz:

  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 2133MHz Kit – CMK16GX4M2A2133C13 – $109.99 Shipped
  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 2400MHz Kit – CMK16GX4M2A2400C14 – $119.99 Shipped
  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 2666MHz Kit – CMK16GX4M2A2666C15 – $129.99 Shipped
  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 3000MHz Kit – CMK16GX4M2B3000C15 – $129.99 Shipped
  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 3200MHz Kit – CMK16GX4M2B3200C16 – $129.99 Shipped
  • Corsair Vengeance LPX 16GB (2x8GB) DDR4 3200MHz Kit – CMK16GX4M2B3200C14 – $176.99 Shipped

G.SKILL Ripjaws V 16GB DDR4 Memory Kits 2133MHz to 3200MHz

  • G.Skill Ripjaws V 16GB (2x8GB) DDR4 2133MHz Kit F4-2133C15D-16GVR $119.99 Shipped
  • G.Skill Ripjaws V 16GB (2x8GB) DDR4 2400MHz Kit F4-2400C15D-16GVR $122.99 Shipped
  • G.Skill Ripjaws V 16GB (2x8GB) DDR4 2666MHz Kit F4-2666C15D-16GVR $121.98 Shipped
  • G.Skill Ripjaws V 16GB (2x8GB) DDR4 3000MHz Kit F4-3000C15D-8GVR $122.99 Shipped
  • G.Skill Ripjaws V 16GB (2x8GB) DDR4 3200MHz Kit F4-3200C16D-8GVK $129.95 Shipped

We hope that you have a better understanding about picking the right DDR4 memory kit for the new Ryzen processor platform. The AMD Ryzen 7 processor and AMD X370 based motherboards love tight timings and high memory clock speeds, but it is clear that AMD and the board makers need to tune for it. Right now we are very early in production and AMD did not give OEMs final processors until just the final two weeks before the platform launched. Performance has been all over the place as a result, but the latest uCode from AMD has improved things and we expect things to get better form this point on.

If you love memory and want to know more we advise taking a look at this ASUS Crosshair VI motherboard overclocking guide that we ran across on overclock.net as they have some nice nuggets in it. This is a guide aimed at extreme overvclockers and claims that the best DRAM configuration at the moment is 2x8GB Samsung B-die based DIMMs and that the worst configuration is dual-rank 2x16GB, especially Hynix-based DRAM (4xSR is best at the moment if you need 32GB and high speed). Other highlights can be found below.

  • Only DRAM timings available are TCL, TRCRDD, TRCWRD, TRPT and TRAS. The only way to affect sub-timings is by lowering your DRAM ratio (essentially behaving like strapping) and increase reference clock. For example at 2400 ratio TWCL=11, at 2133 ratio TWCL=10 and at 1866 ratio TWCL=9.
  • Most CPUs have a memory hole where its unable to train memory from 3350-3450 MHz up to 3500-3600. This means you might be unable to run 3400 MHz DRAM frequency but 3600 is OK.
  • DRAM controller is always running Command Rate = 1T
  • Best performance with Samsung B-die is achieved at 145 MHz REFCLK with 2400 DRAM ratio (3480 MHz) at 11-10-10-10-22 timings. Alternatively 135 MHz REFCLK with 2666 DRAM ratio and 11-11-11-11-22 timings. This depends on the CPU/MB/DRAM capability.
  • DRAM Ratio and timings are applied very early during POST before BIOS has control which might give problems when changing both REFCLK and DRAM Ratio, if you get problems because DRAM Ratio applies first use Retry button.
  • AMD has their own DRAM recovery mechanism that automatically lowers the DRAM Ratio and resets timings if DRAM training fails (F9 0d) during early POST). If you reset at this point you might get stuck at CF or 90 POST codes, manually reset again and the system should POST with the lower ratio and default timings. AMD CBS settings are also reset when this happens.

Update 03-14-2017: AMD said that they have internally observed good results from 2933, 3200, and 3500 MT/s rates with 16GB kits based on Samsung B-die memory chips. Potential kits include:

  • Geil EVO X – GEX416GB3200C16DC [16-16-16-36 @ 1.35v]
  • G.Skill Trident Z RGB Series- F4-3200C16D-16GTZR [16-18-18-36 @ 1.35v] ($189.99 shipped)
  • Corsair CMK16GX4M2B3200C16 VERSION 5.39 [16-18-18-36 @ 1.35v] ($129.99 shipped)