Wednesday, August 10th 2022
Ryzen 7000 Said to Have a DDR5-6000 Memory "Sweet Spot"
If you remember, there were quite a lot of discussions about memory speed "sweet spots" for both the Ryzen 3000- and Ryzen 5000-series, with the user experience not always meeting AMD's sweet spot for memory clocks. Now details of the Ryzen 7000-series memory sweet spot has arrived courtesy of Wccftech and the speed is said to be DDR5-6000. This is 400 MHz higher than the apparent official maximum memory clock speed of DDR5-5600, but as we know, the manufacturer's max memory clock is rarely the actual max. In AMD's case, things obviously work a bit differently, as the Infinity Fabric clock should ideally run at a 1:1 ratio with the memory in the case of the AM4 platform, to deliver best possible system performance and memory latencies.
That said, as we're using DDR memory, the actual clocks are only half of the memory speeds, so the IF clock is operating at no more than 2000 MHz if the memory is DDR4-4000. However, if the same applies to the Ryzen 7000-series, it appears that AMD has managed to bump the IF clocks by a not insignificant 1000 MHz, as the IF fabric would now be operating at up to 3000 MHz. This could see the Ryzen 7000-series offering better memory latencies than Intel's Alder Lake and upcoming Raptor Lake CPUs, as Intel is running DDR5 memory at a 2:1 ratio or a 4:1 ratio. AMD is said to still have a 2:1 ratio as well, but as with the AM4 CPUs, this offers worse overall performance.
Update 11:49 UTC: Yuri Bubliy aka @1usmus has confirmed on Twitter that the max IF frequency of 3000 MHz and it seems like AMD has added a range of new memory and bus related features to the AM5 platform, going by the additional features he posted.
Sources:
Wccftech, @1usmus (1), @1usmus (2)
That said, as we're using DDR memory, the actual clocks are only half of the memory speeds, so the IF clock is operating at no more than 2000 MHz if the memory is DDR4-4000. However, if the same applies to the Ryzen 7000-series, it appears that AMD has managed to bump the IF clocks by a not insignificant 1000 MHz, as the IF fabric would now be operating at up to 3000 MHz. This could see the Ryzen 7000-series offering better memory latencies than Intel's Alder Lake and upcoming Raptor Lake CPUs, as Intel is running DDR5 memory at a 2:1 ratio or a 4:1 ratio. AMD is said to still have a 2:1 ratio as well, but as with the AM4 CPUs, this offers worse overall performance.
Update 11:49 UTC: Yuri Bubliy aka @1usmus has confirmed on Twitter that the max IF frequency of 3000 MHz and it seems like AMD has added a range of new memory and bus related features to the AM5 platform, going by the additional features he posted.
70 Comments on Ryzen 7000 Said to Have a DDR5-6000 Memory "Sweet Spot"
Glad to see this improvement. Ryzen 7000 is born at a more proper time, with 12th gen Core being the pioneer to open up DDR5 market, even though DDR5 is still relatively expensive.
Edit. My buddies 5800X can't even do 1800 but I haven't worked with it personally so not sure what's up with it.
My bet is 5800-6000 will be the usual speed people get, while a few lucky on 1DPC/2dimm boards may do 6200+.
If it's 3GHz, that's one hell of a leap forwards from Zen3...
Come to think of it, AMD has been content to hand the DDR4 crown back to Intel for the past few years. Nothing haopened on the chiplet side, Renoir and Cezanne were a step up but low effort on AMD's part and ignored (aside from a brief stint where 4750G took the WR I think?). I wouldn't be surprised if we see 3 years worth of UMC and IF development all stacked in 7000.
If the rumor is really true and AMD is doing 3000 1:1 leaving intel behind in Gear 2, I'd bet money that they've come up with a new way to link CCD-IOD (or even an extra CCD-CCD). old ass IFOP needs to go. For intel's upcoming chiplet venture (14th) they're bringing out EMIB.
I still have little confidence in their ability to roll out day 1 processors that lives up to those promises. If there's any lesson to be learned in these past three years, wait two or three months if you want a good chance of clocking well.
Bamboozled by AMD IOD once again :( But on the plus side it's still in 1:1 ratio, rather than 1:2 on Intel, so there could be major latency benefits for gaming scenarios.
I wouldn't hold my hopes up for most people achieving the 3000 IF lottery. Most likely the majority will settle at 5600-5800 if prior Ryzen generation are anything to go off of.
We'll see.
Whilst there have been a handful of chips that couldn't handle that, it's always been lowest end of the product stack that didn't quite make those sweet spots.
My FLCK is running at 1900 MHz 1:1 with my 3800 MHz DDR4 memory.This is the "sweet spot" though, which was always a little bit higher than what most chips could do.
My theory, for what it's worth: The leaker assume 4 core per CCX because the I/O die could connect to 4 CCX. (like Zen 2/3 I/O die). Since Zen 4 seem to only have room for 2 CCD, he is probably assume it's back to 2 CCX per die. I only see that happening if AMD put Zen4c on desktop (with or without 3d-vcache). I suppose but not sure that those have 2 8 cores CCX per CCD.
But a theory that i put a bit less weight into would be that Zen 4 have a new topology where they would have a ring bus and a shared l3 for all the 8 cores of the CCD but they would have 2 independent bi directional IF link to the I/O die per CCD instead of 1.
Possible, but in my opinion, it's probably just the I/O die have 4 IF link and he is making assumption.