Speed Step Vs Turbo. What's the difference?

What's the difference between the two when they both adjust the CPU clock dynamically? Also, will i3 330M processor be noticeably faster than i7 640UM for everyday usage? (web browsing, multi tasking, mp3 encoding etc) I think both of CPUs have 4 threads..

 

They're pretty similar in design, but I believe the difference is geared towards purpose (they have different goals in mind). Speedstep is where the CPU has set combinations of voltages and frequencies, and the OS can change between them. The idea behind each combination is to offer the optimal performance at the lowest power. In other words, Speedstep is geared towards using less power while still getting done what needs to be done. It effectively lets the OS choose to "underclock" the CPU to save power when the CPU doesn't need to be running at full capacity.

Turboboost, on the other hand, is all about overclocking the CPU. Rather than going below the base frequency, it only makes the CPU go above it. The concerns for a mobile CPU are power and temperature. If the worst case scenarios of each aren't met, the CPU may be "turboboosted" if needed under a workload. If those worst case scenarios are hit, the reverse occurs until it's back in spec or is back to the base speed. There's another part to Turboboost; it overclocks different cores of a CPU separately, and the amount it can overclock depends on how many cores are active. The multiplier Turboboost depends not only on the active cores but on the specs of the processor, which is to say, different processors allow for different multipliers. Unfortunately, I cannot find those details for the I5 and I7 mobile processors, but just to get an idea of it here is a good example of both of these facts from Wikipedia: Intel Turbo Boost - Wikipedia, the free encyclopedia

The R2 with I5 and I7 have both Speedstep and Turboboost as features, and the R1 and R2 w/Core-I3 just has Speedstep (although you probably can overclock it, just not dynamically). You can tell this is the case because the base frequency of the I3 is much higher than the I5 and I7. The I3 will only be dynamically downclocking, not overclocking like the I5 and I7.

I hope this helps and I didn't get anything too wrong. I am not much more than a novice in these areas.

As for are they noticeably different? That's rather personal, but web browsing and such really doesn't require much. If I was going to buy a computer just for that, I don't think it would be an Alienware tbh, maybe the R1 for the battery life. I think you'll be fine with either.

 

wow..nice post. thanks and repped!

 

rep +1... if you are looking for max performance.. Disable Intel Speed Step. Good Post!

StevenX

 

How is that? to prevent it from "accidentally" down clocking the cpu while gaming etc?

 

Don't do that, unless you're doing that dual IDA thing.