1,4GHz Haswell vs 2,5GHz Ivy - Explain to me

rainydays

macrumors 6502a
Original poster
Nov 6, 2006
886
0
I was surprised to see the 1,4GHz Haswell do about as well as the 2,5GHz Ivy in the geekbench scores. I haven't been updating myself in the world of CPUs for a long time, but I suspect this has mostly to do with the 1,4GHz being able to turbo boost to 2,7GHz?

But how does that translate to real world usage? If a 1,4GHz CPU can perform as well as a 2,7GHz CPU then why isn't it marketed as a 2,7GHz CPU?
What is the downside to turbo boosting compared to a higher base frequency?
 

cinealta

macrumors 6502
Dec 9, 2012
487
6
What is the downside to turbo boosting compared to a higher base frequency?
It's a temporary clock speed and can't be sustained. Thermal override will throttle it back down to 1.4 unlike a CPU designed to be run at a higher baseline constantly.
 

RockSpider

macrumors 6502a
Sep 18, 2014
903
396
I was surprised to see the 1,4GHz Haswell do about as well as the 2,5GHz Ivy in the geekbench scores. I haven't been updating myself in the world of CPUs for a long time, but I suspect this has mostly to do with the 1,4GHz being able to turbo boost to 2,7GHz?

But how does that translate to real world usage? If a 1,4GHz CPU can perform as well as a 2,7GHz CPU then why isn't it marketed as a 2,7GHz CPU?
What is the downside to turbo boosting compared to a higher base frequency?
The best way to find out which is fastest is to convert a BluRay movie into an MP4 or MKV, I'm pretty sure the 2.5ghz Ivy will win hands down.
 

theSeb

macrumors 604
Aug 10, 2010
6,963
91
Poole, England
It's a temporary clock speed and can't be sustained. Thermal override will throttle it back down to 1.4 unlike a CPU designed to be run at a higher baseline constantly.
I agree with you, in theory. Another theory would be that since the 1.4 has a lower TDP, it should be able to sustain turbo boost for much longer without thermal throttling. In theory, communism works.

Therefore I would hold off making any absolute conclusions, until we see some concrete benchmarks and conclusive proof of the thermal efficiency. Geekbench is not a good indicator, because it never stresses a CPU for throttling to become an issue.
 

Osamede

macrumors 6502a
Oct 28, 2009
688
385
"TDP" that Intel offers as a spec seems to be a somewhat vaguely determined measure in reality.
 

rainydays

macrumors 6502a
Original poster
Nov 6, 2006
886
0
The best way to find out which is fastest is to convert a BluRay movie into an MP4 or MKV, I'm pretty sure the 2.5ghz Ivy will win hands down.
Well, that's true if converting movies is the only thing you do.
I'm more interested in how it compares in applications such as image editing and music production. As I understand it turbo boost also works differently depending on how well the application supports threading.

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I agree with you, in theory. Another theory would be that since the 1.4 has a lower TDP, it should be able to sustain turbo boost for much longer without thermal throttling.
That's what I'm thinking too. The Mini should be able to keep a CPU like this cool enough for it to go on turbo boost all the time, effectively making it a 2.7GHz CPU.
 
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