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ssbbb67
Journeyman III

AMD 7950X and 7950X3d memory speed

Hi All, getting ready to purchase one of the two processors listed above.  On the AMD website it says max memory speed is DDR5-5200.  Is that true ???  AMD motherboards says it can take much faster ram.  Any ideas ??? Thx Steven

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I looked at one 7950X motherboard from MSI showing the Memory Specs: https://www.msi.com/Motherboard/PRO-X670-P-WIFI/Specification

Screenshot 2023-02-21 092746.png

Looking at the above Motherboard QVL List it shows most Memory less than 5000 SPD but can be overclocked above 6000Mhz: https://www.msi.com/Motherboard/PRO-X670-P-WIFI/support#mem

But MSI does have a warning about the memory:

Screenshot 2023-02-21 092746.png

I believe what AMD is saying about the maximum Memory speed is its Native speed and not overclocking speed.

Found this tech site that explains about the DDR5 AMD Speeds and it sweet spot: https://wccftech.com/amd-confirms-ryzen-7000-ddr5-6000-memory-sweet-spot-auto-fclk-recommended-for-o...

AMD Ryzen 7000 Confirmed To Have DDR5-6000 Memory Sweet Spot, Best Results Come From Leaving Fabric Clock on Auto

In our coverage of the AMD EXPO technology, we stated how AMD's Ryzen 7000 CPUs will support native DDR5 memory speeds of 5200 Mbps and up to 6400 Mbps overclocking speeds. We also had previously reported that DDR5-6000 will be the sweet spot for AMD Ryzen 7000 CPUs based on the Zen 4 core architecture using the EXPO technology. The DDR5-6000 memory kits that are optimized with EXPO support will offer the best performance with the lowest latency in a 1:1 FCLK mode.

Now as per Robert, we now know that the default FCLK for AMD Ryzen 7000 CPUs is set to 1733 MHz. Robert also states that memory overclocking is a little bit different with Ryzen 7000 since 1:1:1 (FCLK:UCLK:MCLK) isn't important anymore. It is mentioned that to achieve the best results, you should leave the FCLK to auto and overclock the memory modules and memory controller in 1:1 mode. There will be some corner cases where users will be able to get better performance results by hitting over 2 GHz FCLK speeds but those aren't a big priority, as AMD mentions.

At the native setting, DDR5-5200 will operate in a 2:1:1 mode or 1733:2600:2600 clock. Robert also confirmed something that we had stated early on that DDR5-6000 will "Roughly" the sweet spot & by sweet spot, he means the best compromise to cost/stability/performance/availability/ease. So as of right now, we have the following sweet spots as mentioned directly by AMD:

  • Ryzen 3000 "Zen 2" Sweet Spot - DDR4-3800 (Official AMD)
  • Ryzen 5000 "Zen 3" Sweet Spot - DDR4-4000 (Official AMD)
  • Ryzen 7000 "Zen 4" Sweet Spot - DDR5-6000 (Official AMD)

It is stated that DDR5-5200 C28 kits should go really well with Ryzen 7000 too as they are pretty fast but there aren't a lot of kits in those configurations available right now.

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