I'm looking to build and AM5 system and am looking for RAM. On my AM4 machine I have Viper Steel 4400 which is b-die, and I got lucky and all 4 sticks can really tighten down timing a lot.
What's the AM5 equivalent ≈? I read the memory controller lottery plays a big role. Plan to run a 9950x with 2x32GB sticks
What speed can 9000 series take? What kind of timings at those speeds?
Sorry I know it's a broad question, but all i can find is really outdated or contradictory info
SK Hynix (16 Gbit) 2 GB A-Die has the lowest possible timings, excluding the oddball 8 Gbit ones that are in KLEVV FIT V. Those are dual-rank 32GB kits...very strange stuff.
SK Hynix (24 Gbit) 3 GB M-Die has the highest possible frequency currently. Not far behind A-Die for sub-timings. Both M (3GB) and A (2GB) can handle 1.5V just fine with a fan. I would say 1.6V if you have the right cooling, otherwise it will error out.
2x 2R sticks technically best you can do on AMD for the write bandwidth increase, since sweetspot is 6-6400 MT anyway, so the higher MT ratings you can get with 1R sticks are irrelevant. Going for A die if 2x 2R, or M die if 2x 1R, so 2x 32 GB, or 2x 24 GB.
Avoid any 4x setup, or even motherboards with four slots unless they're the fancy ASUS ones with optimized traces, I forget what they're called and am too lazy to look it up.
With DDR5, a 2x setup gives you more than enough capacity on dual channel systems anyway (64, 96, 128 GB). For the higher capacities, you want quad or higher channel anyway.
Note the bottleneck is still the IF, which clocks at best around 2000 MHz, maybe ~2100 or 2200 if you're extremely lucky. 6000 MT '1:1' means the memory and memory controller are both running at 3000 MHz, which still means the IF limits actual benefits of that, since it's 1.5:1 to the actual cores.
Explained here.
Zen 6 may fix the IF bottleneck as new packaging and less latency penalty, which
in theory should mean X3D cache is less needed, that was a mitigation for the latency penalty of chiplet design as AMD built them.
Note that the IF being 2000 MHz essentially means it didn't get faster since AM4, X570 and Zen 3 could do 2000 MHz IF/FCLK for '1:1' with 4000 MT/2000 MHz DDR4, but more common was 3800 MT.
I ran a 5800X3D with 4000/14 DRAM and 2000 MT IF, still kinda miss that rig.
Nitropath, that's what ASUS calls their improved traces, supposedly brings 4 slot boards to the level of 2 slot boards, but I am skeptical, and irritated they didn't put it on their two slot boards too.
