4 ms·

> And why does the article say "These Altra CPUs have no turbo mechanism" right below a graphic saying "3.0 Ghz Turbo"? These chips obviously have variable clo

> And why does the article say "These Altra CPUs have no turbo mechanism" right below a graphic saying "3.0 Ghz Turbo"? These chips obviously have variable clock speed, but apparently nothing like the complicated boost mechanisms on recent x86 processors. My guess is that Turbo speed here is simply full speed, and doesn't depend significantly on how many cores are active, and doesn't let the chip exceed its nominal TDP for short (or not so short) bursts the way x86 processors do.

rbanffy 6y ago
> and doesn't depend significantly on how many cores are active, and doesn't let the chip exceed its nominal TDP for short (or not so short) bursts the way x86 processors do Either that, or 3 GHz always exceeds the envelope and the chip is throttling clocks down all the time to keep itself inside the allowed power envelope.
zozbot234 6y ago
> doesn't let the chip exceed its nominal TDP for short (or not so short) bursts the way x86 processors do. That's more of an artifact of how TDP is defined than anything else. I doubt that this could peg even a single core at 3.0 GHz given a reasonable cooling setup, let alone run all cores @ 3.0 GHz.
- greggyb 6y ago
  Why do you think this won't keep a single core at 3.0GHz? You can get ~3.4GHz average sustained all-core speed on a 3990x (64-core, nominal 280W TDP). This is with an off-the-shelf AIO cooler.[0] Note: top-end air coolers are often competitive with AIOs, and can be had for $80-$100.[1] If you're buying a several thousand dollar CPU, dropping even $500 (much higher than you'd need for closed loop liquid or high-end air cooling) on cooling doesn't seem unreasonable. [0] https://www.anandtech.com/show/15483/amd-threadripper-3990x-review/2 https://www.anandtech.com/show/15483/amd-threadripper-3990x-... [1] https://www.youtube.com/watch?v=7VzXHUTqE7E https://www.youtube.com/watch?v=7VzXHUTqE7E
  - stan_rogers 6y ago
    Neither the AIO nor the large tower (air) cooler are going to fly in a sever rack.
    - greggyb 6y ago
      No. Servers will be utilizing jet-sounding fans, or air conditioned intake, or rack-level water cooling, or any number of other cooling solutions that can handle high the heat output. 250W is not an absurd figure to shove in a server CPU. If you're buying an 80-core CPU, you're not going to be skimping on the cooling solution. Especially given the target market for Ampere is cloud providers, you can expect these to be racked in enclosures that provide sufficient cooling for their operational needs.

rbanffy 6y ago

> and doesn't depend significantly on how many cores are active, and doesn't let the chip exceed its nominal TDP for short (or not so short) bursts the way x86 processors do Either that, or 3 GHz always exceeds the envelope and the chip is throttling clocks down all the time to keep itself inside the allowed power envelope.

zozbot234 6y ago

> doesn't let the chip exceed its nominal TDP for short (or not so short) bursts the way x86 processors do. That's more of an artifact of how TDP is defined than anything else. I doubt that this could peg even a single core at 3.0 GHz given a reasonable cooling setup, let alone run all cores @ 3.0 GHz.

greggyb 6y ago
Why do you think this won't keep a single core at 3.0GHz? You can get ~3.4GHz average sustained all-core speed on a 3990x (64-core, nominal 280W TDP). This is with an off-the-shelf AIO cooler.[0] Note: top-end air coolers are often competitive with AIOs, and can be had for $80-$100.[1] If you're buying a several thousand dollar CPU, dropping even $500 (much higher than you'd need for closed loop liquid or high-end air cooling) on cooling doesn't seem unreasonable. [0] https://www.anandtech.com/show/15483/amd-threadripper-3990x-review/2 https://www.anandtech.com/show/15483/amd-threadripper-3990x-... [1] https://www.youtube.com/watch?v=7VzXHUTqE7E https://www.youtube.com/watch?v=7VzXHUTqE7E
- stan_rogers 6y ago
  Neither the AIO nor the large tower (air) cooler are going to fly in a sever rack.
  - greggyb 6y ago
    No. Servers will be utilizing jet-sounding fans, or air conditioned intake, or rack-level water cooling, or any number of other cooling solutions that can handle high the heat output. 250W is not an absurd figure to shove in a server CPU. If you're buying an 80-core CPU, you're not going to be skimping on the cooling solution. Especially given the target market for Ampere is cloud providers, you can expect these to be racked in enclosures that provide sufficient cooling for their operational needs.