AMD recently unveiled the company's Ryzen 7000 (Raphael) processors. Robert Hallock, the Director of Technical Marketing at AMD, has divulged additional information regarding the best RAM for the new Zen 4 chips.
Hallock commented on AMD's official Discord channel (via Bionic_squash) that memory overclocking on the Ryzen 7000 processors differs slightly from the previous Ryzen 5000 (Vermeer) chips. For starters, Hallock confirmed that it's no longer essential to maintain a 1:1:1 ratio with the Infinity Fabric Clock (FCLK), unified memory controller clock (UCLK), and memory clock (MEMCLK). Instead, he recommends users leave the FCLK on the auto setting and overclock the DDR5 memory modules and the memory controller in a 1:1 ratio. As a result, the best configuration is Auto:1:1.
The Zen 4 parts have a default FCLK of 1,733 MHz, supporting DDR5-5200 memory by default. Hallock believes that DDR5-6000 will be the sweet spot for Zen 4 based on cost, stability, performance, availability, and ease. In contrast, Zen 3's sweet spot was at DDR4-3600 (1,800 MHz FCLK), with DDR4-4000 (2,000 MHz FCLK) being the golden standard. Nonetheless, Hallock said that in some scenarios, when surpassing a 2,000 MHz FCLK could yield better performance. However, it shouldn't be the priority for most users. We'll take AMD's word until we can run our RAM benchmarks on Zen 4.
Current DDR5-6000 16GB (2x8GB) memory kits start at $165 whereas the 32GB (2x16GB) offerings retail for $219. A decent DDR4-4000 memory kit costs half of a DDR5 memory kit. However, we already knew beforehand that migration to AMD's AM5 socket commands a small fortune due to the chipmaker's decision not to maintain DDR4 support on Zen 4. Although pricing for DDR5 has improved over the last few months, it still carries a significant premium over DDR4. There aren't any shortages anymore, but it's still more expensive to produce DDR5. Nevertheless, AMD is optimistic that DDR5 supply and pricing should continue to get better.
As always, it's recommended to choose a dual-DIMM memory kit over a quad-DIMM configuration for Ryzen 7000. Dual-DIMM setups are better for signal routing and less stressful on the processor's IMC (integrated memory controller). For example, AMD only guarantees DDR5-5200 support on a 1DPC (DIMM per channel) configuration. In a 2DPC scenario, the official memory speed drops to DDR5-3600.
AMD's Ryzen 7000 processors will arrive on the retail market on September 27, along with the new 600-series motherboards and EXPO-certified DDR5 memory.
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Zhiye Liu
RAM Reviewer and News Editor
Zhiye Liu is a Freelance News Writer at Tom’s Hardware US. Although he loves everything that’s hardware, he has a soft spot for CPUs, GPUs, and RAM.
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12 CommentsComment from the forums
thisisaname Hmmm so AMD only guarantees DDR5-5200 support on a 1DPC (DIMM per channel) configuration. In a 2DPC scenario, the official memory speed drops to DDR5-3600.
Two things spring to mind if the sweet spot is DDR5-6000 the grantee supported speed is only 5200 does seem a little low and 2DPC speed of only 3600 is very slow. I wonder how much that is going to affect proformance.Reply
shady28 thisisaname said:
Hmmm so AMD only guarantees DDR5-5200 support on a 1DPC (DIMM per channel) configuration. In a 2DPC scenario, the official memory speed drops to DDR5-3600.
Two things spring to mind if the sweet spot is DDR5-6000 the grantee supported speed is only 5200 does seem a little low and 2DPC speed of only 3600 is very slow. I wonder how much that is going to affect proformance.I think this is going to wind up being just like their "Zen 3 works best at DDR4-4000" thing. Most can get to 3600 (not all), many can get to 3800 (but fewer), but 4000 is like less than 5% of Zen 3 owners.
Next sneaky move would be to make sure reviewers are also provided with 'binned' high quality chips.
Reply
I'm confused. Isn't DDR5 inherently double channel? Two modules will make it quad channel, right? I hope it will explained in the review. I'm lost in all of this.
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wifiburger 5200 default speed is 1 dimm,
2 dimms drops to 3600 speed and their support page don't even support 4 dimms by defaultto me it looks like the IMC is crap, typical AMD of course
"sweet spot" BS from AMD; I will believe when 99.9% of Zen4 samples hit ddr6000
people thinking IF goes to 3000mhz when AMD said ddr6000....... lol
Now, let's do some calculations, because why does AMD list 5200 1 DIMM & 3600 2 DIMM by default ?
1733mhz IF x 32 bits = 55.4Gb/s bandwith
5200 1 dimm bandwith = ~41.6Gb/s
3600 2 dimm bandwith = ~57.6Gb/s
5200 2 dimm bandwith = ~83.2Gb/sI'm assuming you still reach 83.2Gb/s with 5200 2 dimms with 1733IF clock ?
I guess there's some changes to async operations or IF is 64bits per clock ?Reply
mamasan2000 wifiburger said:
5200 default speed is 1 dimm,
2 dimms drops to 3600 speed and their support page don't even support 4 dimms by defaultto me it looks like the IMC is crap, typical AMD of course
"sweet spot" BS from AMD; I will believe when 99.9% of Zen4 samples hit ddr6000
people thinking IF goes to 3000mhz when AMD said ddr6000....... lol
Now, let's do some calculations, because why does AMD list 5200 1 DIMM & 3600 2 DIMM by default ?
1733mhz IF x 32 bits = 55.4Gb/s bandwith
5200 1 dimm bandwith = ~41.6Gb/s
3600 2 dimm bandwith = ~57.6Gb/s1 DIMM PER channel. And it's going to be dualchannel motherboards, just as we have with DDR4. So that means 2 DIMM sticks.
What I am seeing is, just like with quadrank per channel on AMD and DDR4, it's going to run like crap.Reply
wifiburger tommo1982 said:
I'm confused. Isn't DDR5 inherently double channel? Two modules will make it quad channel, right? I hope it will explained in the review. I'm lost in all of this.1 dimm ddr5 = dual channel ddr5 (half bandwidth) = same as 1 dimm ddr4 single channel full bandwidth
2 dimm ddr5 = qual channel ddr5
it's the same as 2 dimm dual channel ddr4 for bandwidthReply
-Fran- Hm... I don't like having to rely on the motherboard to set the IF speeds. That being said, I'll wait for reviews to show if this has any meaningful impact or not.
I was hoping for 3Ghz IF. Bummer.
Regards.
Reply
-Fran- said:
Hm... I don't like having to rely on the motherboard to set the IF speeds. That being said, I'll wait for reviews to show if this has any meaningful impact or not.I was hoping for 3Ghz IF. Bummer.
Regards.
Where do you set IF speeds? Haven't seen the option anywhere in my BIOS. I have a Ryzen 5 Pro 3350G, so I might be unable to set it manually. I also have an ASRock B450M Steel Legend.
Reply
wifiburger said:
1 dimm ddr5 = dual channel ddr5 (half bandwidth) = same as 1 dimm ddr4 single channel full bandwidth2 dimm ddr5 = qual channel ddr5
it's the same as 2 dimm dual channel ddr4 for bandwidthHow will the mainboard deal with four RAM slots occupied? Will it run as quad chanell with one DIMM full bandwith per chanell like DDR4?
Reply
-Fran- tommo1982 said:
Where do you set IF speeds? Haven't seen the option anywhere in my BIOS. I have a Ryzen 5 Pro 3350G, so I might be unable to set it manually. I also have an ASRock B450M Steel Legend.I don't know how it is called in AsRock BIOS'es, but you can find the "FCLK" (fabric clock) or "BCLK" (bus clock). Don't confuse it with the memory speed though.
And, when in doubt, RTFM.
Regards.
Reply
