- Jan 12, 2019
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People seem to have overlooked the fact that Ryzen 3700X "features" very low RAM write speeds:
1) https://www.overclock3d.net/reviews...n_7_3700x_ryzen_9_3900x_x470_vs_x570_review/9
2) https://www.tweaktown.com/reviews/9051/amd-ryzen-3900x-3700x-zen2-review/index3.html
which, according to TweakTown, is explained by:
"In memory bandwidth, we see something odd, the write speed of AMD's 3700X, and that's because of the CDD to IOD connection, where the writes are 16B/cycle on the 3700X, but it's double that on the 3900X. AMD said this let them conserve power, which accounts for part of the lower TDP AMD aimed for. AMD says applications rarely do pure writes, but it did hurt the 3700X's performance in one of our benchmarks on the next page. Memory latency is a bit high at stock, but you can overclock the memory quite easily".
Overclockers.com offers a similar explanation:
“This is an expected result. Client workloads do very little pure writing, so the CCD/IOD link is 32B/cycle while reading and 16B/cycle for writing. This allowed us to save power and area inside the package to spend on other, more beneficial areas for tangible performance benefits”.
This sounds extremely odd considering the fact that this CPU consumes up to 120W under load without any overclocking involved. Also memory copy seems not to be affected at all.
I wonder if someone with connections to AMD could dig deeper and find out the root cause of this anomaly because if it's real then the Ryzen 3600X CPU might feature "proper" write speeds despite it being a lower tier CPU.
1) https://www.overclock3d.net/reviews...n_7_3700x_ryzen_9_3900x_x470_vs_x570_review/9
2) https://www.tweaktown.com/reviews/9051/amd-ryzen-3900x-3700x-zen2-review/index3.html
which, according to TweakTown, is explained by:
"In memory bandwidth, we see something odd, the write speed of AMD's 3700X, and that's because of the CDD to IOD connection, where the writes are 16B/cycle on the 3700X, but it's double that on the 3900X. AMD said this let them conserve power, which accounts for part of the lower TDP AMD aimed for. AMD says applications rarely do pure writes, but it did hurt the 3700X's performance in one of our benchmarks on the next page. Memory latency is a bit high at stock, but you can overclock the memory quite easily".
Overclockers.com offers a similar explanation:
“This is an expected result. Client workloads do very little pure writing, so the CCD/IOD link is 32B/cycle while reading and 16B/cycle for writing. This allowed us to save power and area inside the package to spend on other, more beneficial areas for tangible performance benefits”.
This sounds extremely odd considering the fact that this CPU consumes up to 120W under load without any overclocking involved. Also memory copy seems not to be affected at all.
I wonder if someone with connections to AMD could dig deeper and find out the root cause of this anomaly because if it's real then the Ryzen 3600X CPU might feature "proper" write speeds despite it being a lower tier CPU.
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