4 ms·

Apple's chip has 4200Mhz RAM. Wouldn't it be fair to have both ram speeds the same? Also it's a set of benchmarks some random person did. It's interesting an

by Jonnax 6y ago

Apple's chip has 4200Mhz RAM. Wouldn't it be fair to have both ram speeds the same? Also it's a set of benchmarks some random person did. It's interesting and useful information. They aren't a publication doing a comparison.

jzelinskie 6y ago
For Zen, you actually want to run your memory clock at a multiple of the FCLK and not as high as possible. So making the RAM frequency the same as the M1 might have actually harmed performance.
- eloff 6y ago
  I don't think that's true with Zen 3. If you have a source to the contrary I'm interested to see it.
- reissbaker 6y ago
  I've read various theories about the right memory clock speed to use for Zen, but in all the gaming benchmarks I've seen, faster RAM clock speed ends up resulting in higher performance.
  - eloff 6y ago
    Especially true with Zen 3.
  - scottlamb 6y ago
    > I've read various theories about the right memory clock speed to use for Zen, but in all the gaming benchmarks I've seen, faster RAM clock speed ends up resulting in higher performance. Got citations? Better yet if there are any developer-oriented benchmarks. I'm building a Zen3 machine to use as a workstation. I just ordered DDR4-3600 RAM (but can still probably change the order if I made the wrong call). The specifications [1] only mention 3200 Mhz, so I think even that is overclocking the I/O chiplet to run at 1:1. I want a stable development machine rather than a toy so I wasn't planning to go further. I also read an interview [2] (most interesting part quoted below) which suggests there's diminishing utility in going beyond 3600. > Okay, so what’s the best price/performance? > DDR4-3600 continues to be a “sweet spot.” The kits are inexpensive, widely available, perform well, and have good compatibility. Is it the best in every category? No, but that’s not what the sweet spot is. 3600 is a good bet because it’s a good value in perf/$ for someone who wants to plug and play. Is it the best possible performance? No. Is it close? Yes, and without tinkering. > What’s the best memory, even if i have to overclock? > Probably very tight timing 3600 or 3800, just like the Ryzen 3000 Series. The timings on these memory bins can be super aggressive versus higher memory speed grades, and that usually overpowers frequency. My RAM is actually CL18 DDR4-3600. Maybe I should have gone with CL16...I'm not sure how much it really matters for development though, and I'm getting 64 GiB of RAM so the cost per byte adds up a bit more than it does for a gamer buying 16 GiB. [1] https://www.amd.com/en/products/cpu/amd-ryzen-9-5950x https://www.amd.com/en/products/cpu/amd-ryzen-9-5950x [2] https://videocardz.com/newz/amd-robert-hallock-promises-ryzen-5000-undervolting-with-new-functionality https://videocardz.com/newz/amd-robert-hallock-promises-ryze...
    - reissbaker 6y ago
      Here's one side-by-side you can watch with the same games being played on the same Zen-based system, but with varying RAM clock speeds: https://youtu.be/8H0DEkpEDCE https://youtu.be/8H0DEkpEDCE Generally, the highest-clocked RAM got the best average and min FPS in the games tested. I'm having trouble finding it now, but IIRC I also once saw a side-by-side comparing different RAM latencies, and the differences were not enough to outweigh clock speeds; i.e. overclocking with worse latencies was better than lower latency but lower clock. That being said I've seen non-gaming benchmarks that imply that there is a 3600mhz sweet spot. So it may vary based on workload. I haven't looked into that closely though — I was looking at benchmarks when building a gaming PC, so I had a specific focus :)
em500 6y ago
> Apple's chip has 4200Mhz RAM. Wouldn't it be fair to have both ram speeds the same? No it wouldn't, because Apple is selling that as their supported configuration. If that crashes due to ram / chip instability you can take it back to Apple to get a new one with the expected performance. That's completely different from your homebrew ram overclock, if that config doesn't stay stable, tough luck.

by Jonnax 6y ago

jzelinskie 6y ago

For Zen, you actually want to run your memory clock at a multiple of the FCLK and not as high as possible. So making the RAM frequency the same as the M1 might have actually harmed performance.

eloff 6y ago
I don't think that's true with Zen 3. If you have a source to the contrary I'm interested to see it.
reissbaker 6y ago
I've read various theories about the right memory clock speed to use for Zen, but in all the gaming benchmarks I've seen, faster RAM clock speed ends up resulting in higher performance.
- eloff 6y ago
  Especially true with Zen 3.
- scottlamb 6y ago
  > I've read various theories about the right memory clock speed to use for Zen, but in all the gaming benchmarks I've seen, faster RAM clock speed ends up resulting in higher performance. Got citations? Better yet if there are any developer-oriented benchmarks. I'm building a Zen3 machine to use as a workstation. I just ordered DDR4-3600 RAM (but can still probably change the order if I made the wrong call). The specifications [1] only mention 3200 Mhz, so I think even that is overclocking the I/O chiplet to run at 1:1. I want a stable development machine rather than a toy so I wasn't planning to go further. I also read an interview [2] (most interesting part quoted below) which suggests there's diminishing utility in going beyond 3600. > Okay, so what’s the best price/performance? > DDR4-3600 continues to be a “sweet spot.” The kits are inexpensive, widely available, perform well, and have good compatibility. Is it the best in every category? No, but that’s not what the sweet spot is. 3600 is a good bet because it’s a good value in perf/$ for someone who wants to plug and play. Is it the best possible performance? No. Is it close? Yes, and without tinkering. > What’s the best memory, even if i have to overclock? > Probably very tight timing 3600 or 3800, just like the Ryzen 3000 Series. The timings on these memory bins can be super aggressive versus higher memory speed grades, and that usually overpowers frequency. My RAM is actually CL18 DDR4-3600. Maybe I should have gone with CL16...I'm not sure how much it really matters for development though, and I'm getting 64 GiB of RAM so the cost per byte adds up a bit more than it does for a gamer buying 16 GiB. [1] https://www.amd.com/en/products/cpu/amd-ryzen-9-5950x https://www.amd.com/en/products/cpu/amd-ryzen-9-5950x [2] https://videocardz.com/newz/amd-robert-hallock-promises-ryzen-5000-undervolting-with-new-functionality https://videocardz.com/newz/amd-robert-hallock-promises-ryze...
  - reissbaker 6y ago
    Here's one side-by-side you can watch with the same games being played on the same Zen-based system, but with varying RAM clock speeds: https://youtu.be/8H0DEkpEDCE https://youtu.be/8H0DEkpEDCE Generally, the highest-clocked RAM got the best average and min FPS in the games tested. I'm having trouble finding it now, but IIRC I also once saw a side-by-side comparing different RAM latencies, and the differences were not enough to outweigh clock speeds; i.e. overclocking with worse latencies was better than lower latency but lower clock. That being said I've seen non-gaming benchmarks that imply that there is a 3600mhz sweet spot. So it may vary based on workload. I haven't looked into that closely though — I was looking at benchmarks when building a gaming PC, so I had a specific focus :)

em500 6y ago

> Apple's chip has 4200Mhz RAM. Wouldn't it be fair to have both ram speeds the same? No it wouldn't, because Apple is selling that as their supported configuration. If that crashes due to ram / chip instability you can take it back to Apple to get a new one with the expected performance. That's completely different from your homebrew ram overclock, if that config doesn't stay stable, tough luck.