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AMD was also measurably slower to begin with, in terms of per-core performance. Not just by some small number; depending on the benchmark the difference can hit

by 013a 7y ago

AMD was also measurably slower to begin with, in terms of per-core performance. Not just by some small number; depending on the benchmark the difference can hit as high as 40% on the latest architectures. What they lack in single-core perf they make up for in a vastly superior multi-core architecture. Also, something everyone seems to forget: All of these cloud providers are running Skylake chips, which were launched in 2015. Google Cloud in particular will even give you chips OLDER than Skylake by default if you don't specifically request Skylake. Even assuming instances like an AWS m5a are running on Zen 1, not Zen 2, that's a 2017 architecture. So you're presented with all these graphs that say "AMD only lost 5%, Intel lost 25%, fuck Intel" but the reality is that Intel was previously far faster than AMD, and they're not even fabbing their best designs for the data center. Intel definitely had more vulnerabilities and they WERE hit harder, but its more nuanced than just blindly wondering why more cloud providers aren't making a fleet-wide switch to AMD.

nolok 7y ago
> AMD was also measurably slower to begin with, in terms of per-core performance. Not so surprising now that we know Intel merely skipped a lot of checks to get there though. I mean a lot of the vulnerabilities impacting Intel only have been the likes of "when predicting, the processor does it even it shouldn't to avoid the delay from checking". Is it really fair then to say that AMD doing it the proper way was slower, or that the loss of performance of Intel can't be used as a way to congratulate AMD on being safer on that front ?
- qes 7y ago
  It would be fair to say that if AMD had the features but implemented in a way that wasn't vulnerable. That, however, is not the case. AMD simply lacks the features.
kllrnohj 7y ago
> depending on the benchmark the difference can hit as high as 40% on the latest architectures That's a technically true but also misleading statement. It is exclusively on heavy AVX loads that any such delta appears. If you're not using AVX, then the single-thread differences are ~15% or less. So Intel losing 25% does now potentially put them behind on most single-threaded workloads.

by 013a 7y ago

nolok 7y ago

> AMD was also measurably slower to begin with, in terms of per-core performance. Not so surprising now that we know Intel merely skipped a lot of checks to get there though. I mean a lot of the vulnerabilities impacting Intel only have been the likes of "when predicting, the processor does it even it shouldn't to avoid the delay from checking". Is it really fair then to say that AMD doing it the proper way was slower, or that the loss of performance of Intel can't be used as a way to congratulate AMD on being safer on that front ?

qes 7y ago
It would be fair to say that if AMD had the features but implemented in a way that wasn't vulnerable. That, however, is not the case. AMD simply lacks the features.

kllrnohj 7y ago

> depending on the benchmark the difference can hit as high as 40% on the latest architectures That's a technically true but also misleading statement. It is exclusively on heavy AVX loads that any such delta appears. If you're not using AVX, then the single-thread differences are ~15% or less. So Intel losing 25% does now potentially put them behind on most single-threaded workloads.