Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Why is the 17 faster than the 15 ?
- Thread starter jetjaguar
- Start date
- Sort by reaction score
no clue, wondering that too. i mean it's the same specs, and the 17" needs more power for the screen too!
there's a lot of trickery involved with the i7 clock speeds and core/thread enabling/disabling that could cause one machine to do something different in a different situation.
Maybe it was cooler in the room when the 17" was run? Maybe the 15 has a smaller fan that keeps the turbo boost from reaching the same sustained ghz?
who knows. It's interesting, though.
Maybe it was cooler in the room when the 17" was run? Maybe the 15 has a smaller fan that keeps the turbo boost from reaching the same sustained ghz?
who knows. It's interesting, though.
Trickery? I call it BS. Apple outlets and other partner sites have always ranked the 17" higher. Media seems to fudge numbers to make a better case for the price. Only thing usually faster is maybe the GPU. Same chip but as noted earlier maybe they don't underclock it in the 17". Turbo multiplier bins are most likely the same as Intel usually doesn't "custom" make chips for Apple and Apple rarely gets into such low level tinkering. So again, BS.
I don't know.
But I suspect, it may have to do with with the 17's larger surface area and interior volume, so it would be slightly better at conducting away the heat. Better heat management means the core i7/i5s can overclock themselves (with turbo boost) more of the time.
But I suspect, it may have to do with with the 17's larger surface area and interior volume, so it would be slightly better at conducting away the heat. Better heat management means the core i7/i5s can overclock themselves (with turbo boost) more of the time.
17" usually has more room, layout might be slightly more optimized.
17" often runs at slightly higher voltage, etc.
17" often runs at slightly higher voltage, etc.
I think this is the best explanation. Perhaps Apple saw the heat problems of the 15" and underclocked it. Coincidentally, StefSSU mentioned the same thing a few minutes ago. It's definitely the turbo boost technology and its heat sensors.
Not an expert here, but I think the 17" just has more physical room in its chassis to allow for better cooling. The processor is then able to turbo boost higher and turbo boost longer without throttling down because of excess heat. That's the best explanation I have.
It could be that the test scores vary from run to run and the one that was chosen happened to show the 17 as faster than the 15. If the test was run a large number of times, the scores would probably show to be statistically similar.
To say Apple underclocked the 15" is a misrepresentation of what's going on. Apple didn't underclock anything. If they had they wouldn't be able advertise it at that base clock speed, since it would fall below it. The CPU overclocks itself for as long as it can until it reaches a certain temperature, the it backs off. What others are saying here is that the 15" reaches that target temperature sooner, so it starts stepping back down to the base clock speed sooner. I suspect that if you took the systems out of the case, and provided them with the exact same cooling, that they would behave exactly the same.
Gotcha.
So basically, for those planning to upgrade their 15" processors from 2.2GHz to 2.3GHz, they're better off buying a stock 17" 2.2GHz for almost the same cost without the BTO hassle. The stock 17" beats the pants out of an upgraded 15" due to heat dissipation. And you have a cooler machine as well.
Except for two things:
- people usually buy 15 or 17 based on size not relative performance
- 17" runs at 1900 x 1200 which will be more intensive to run at the native res. than either of the 15"s so you will get lower frame rates
Because of the ventilation
Size of 17 inch chasis makes it more effective in flow of the heat.
which will increase the maximum performance of the same cpu.
Size of 17 inch chasis makes it more effective in flow of the heat.
which will increase the maximum performance of the same cpu.