Laptop vs ultrabook vs desktop i7 equivalent?

[wand3r3r]

Has anyone followed the latest mobile processors closely enough to fairly accurately compare them?

For example ultrabooks i7's with ~1.7Ghz and whatever the wattage seem like they must be somewhat neutered compared to e.g. i7 3830ms at ~2.4-3.3GHz or are they mainly just downclocked. Then compared to ~4770k/3770k.

Someone had been complaining about performance on an expensive ultrabook but without even knowing the true performance I'd guess its at least half as fast due to the clock speed alone but it'd be interesting to know a little more accurately the performance across these three lines (desktop, mobile, ulv i7's).

The gtx 680m comes to mind as its equal to the gtx 660 desktop part (or was it 660 ti) so it makes an easy reference.

Is it possible to say an i7 3770/4770 at e.g. 0.7GHz == 1.7ghz ulv etc. (In general) those numbers are of course made up.

 

[Concillian]

Some of the ultrabook i7s are 2C / 4T and will perform more like a desktop i3.

Check out the Ivy bridge page at Wikipedia:
http://en.wikipedia.org/wiki/Ivy_Bridge_(microarchitecture)

a mobile i7 could be anything from:
2C / 4T @ 1.9 GHz --> 3.0 GHz turbo
all the way up to
4C / 8T @ 3.0 GHz --> 3.9 turbo

The i7 "branding" means top tier for a given market segment. In the ULV ultrabook segment, this can mean ~i3 desktop performance, but it is considered top tier performance at that low power consumption.

The result is that there isn't a clear comparison between a desktop i7 and a mobile i7. There are so many variations of mobile i7s that you really have to compare a specific model.

You can pretty much compare clock speed to get an equivalence, but you can't necessarily gauge core to core. 2C / 4T is "good enough" in many general use categories that it will "feel" every bit as fast as a 4C / 8T CPU at the same speed... But in other usage it could feel half as fast. It gets more difficult to define when you look at differences in the number of cores, it becomes highly dependent on the actual loadings seen.