Question AM4 theoretical question regarding DDR4 memory speeds

Hans Gruber

Golden Member
Dec 23, 2006
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567
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AMD says they will continue to support the AM4 platform. I have been thinking about the memory speeds. Could AMD create a XMP like OCing setting where the minimum memory speed would be 3200mhz. The standard DDR4 default clock speed is 2133mhz. AM4 maxes out the memory divider @ 3800mhz memory speeds. Could they simply push the beginning medium memory speed to 3200mhz and thus push the 1:1 divider ratio up 1037mhz (2133-3200mhz) as a starting point. In theory that would prevent the memory divider from introducing massive memory latency above 3800mhz to a new max memory 1:1 ratio of 4807mhz DDR4 memory speed.

Essentially just sliding up the starting point of the memory from 2133mhz to 3200mhz. If this is possible that would significantly improve AM4 performance from the B350 all the way up to the X570 boards since AMD fixed the memory issues affecting the B350/X370 boards with the latest AGESA release.

DDR4 memory kits have a lot of performance that is being left on the table. I have some Hynix CRJ sticks that says on the packaging the sticks are capable of 4500mhz+.

Thoughts on this being possible?
 

Hotrod2go

Member
Nov 17, 2021
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AMD says they will continue to support the AM4 platform. I have been thinking about the memory speeds. Could AMD create a XMP like OCing setting where the minimum memory speed would be 3200mhz. The standard DDR4 default clock speed is 2133mhz. AM4 maxes out the memory divider @ 3800mhz memory speeds. Could they simply push the beginning medium memory speed to 3200mhz and thus push the 1:1 divider ratio up 1037mhz (2133-3200mhz) as a starting point. In theory that would prevent the memory divider from introducing massive memory latency above 3800mhz to a new max memory 1:1 ratio of 4807mhz DDR4 memory speed.

Essentially just sliding up the starting point of the memory from 2133mhz to 3200mhz. If this is possible that would significantly improve AM4 performance from the B350 all the way up to the X570 boards since AMD fixed the memory issues affecting the B350/X370 boards with the latest AGESA release.

DDR4 memory kits have a lot of performance that is being left on the table. I have some Hynix CRJ sticks that says on the packaging the sticks are capable of 4500mhz+.

Thoughts on this being possible?
I agree with you that DDR4 still has a lot of usage in it for many yrs to come. Even DDR3 is still usable today, of course depending on the usage model for the system. The thing is though, that with high speed DDR4, significant voltage is needed to maintain stability above 4000MHz without ridiculously loose timings. Although you have Hynix CJR sticks that claim 4500Mhz +, only high end motherboards are capable of supporting that & as an educated guess, I'd say at least 1.50v minimum. I have a 32GB kit of Hynix DJR with XMP of 4600Mhz CL19 but at 1.50v of course. They will even do 4800MHz with 1.52v, thus clutching at the heels of base level DDR5 speed.

But to your point on AMD creating XMP profiles with DDR4, I think they aren't going to do that at this point in time cause' they have to encourage the market transition to the new shiny DDR5 standards. I mean how else can they keep profits coming in year after year without some new shiny product(s) like DDR5 platforms for example? even though the extra bandwidth looks great in synthetic benchmarks, to end users in the real world, it will be a placebo effect for some yrs to come still. It's like at what point is too much bandwidth excessive for daily tasks? I'm speaking generally here & there will always be niche cases where more bandwidth is essential of course but to the bulk of the market, its useless today.
 

DrMrLordX

Lifer
Apr 27, 2000
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AMD had AMP, and it never went anywhere. They probably won't go through that again. Definitely not for a legacy product.
 

Hans Gruber

Golden Member
Dec 23, 2006
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567
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It would be a simple bios setting. Instead of base 2133mhz the DDR4 memory. The new threshold would be 3000-3200mhz and the memory dividers would still be the 1:1 ratio above the current maximum 3800mhz to either 4667mhz or 4867mhz. AMD is keeping AM4 around. There are a lot of people who have high clocking sticks. Even running Cas 16 or Cas 18 @4000mhz without the latency penalty would be a nice bump for a AM4 Zen 2 or Zen 3 CPU.

The point is keeping the 1:1 memory ratio and the simple way to do that is slide up the base DDR4 frequency with the same table/hierarchy structure of the memory timing. Since I am talking about a bios setting tweak. They could keep the standard base 2133mhz frequency and have the increased frequency as a separate setting that OC'ers enable.
 

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