What is the difference between a desktop and mobile Haswell i7? Obviously, the desktop CPU will run at a higher frequency and also use more power, but how would they compare if they were both clocked at the same speed? Do mobile i7s have less L2/3 cache than a desktop i7? I'm just curious, since I've always assumed they're the same outside of clock speed.
Well for one thing, unless we're talking the -QM i7's, the mobile chips are only dual cores. If we are talking the -QM chips, desktop isn't neutered to fit into a specific thermal envelope, and then you have the 'K' chips with an unlocked multiplier with which to overclock.
There might be looser timings in a mobile i7 compared to a desktop i7 which may mean slightly lower performance. But that is only speculation.
I was actually interested in this myself. But it will have to wait until I upgrade my current PC to a Haswell i5 CPU and hopefully be able to afford ThinkPad T540p with a Core i7-4700mq. I would need to disable hyper threading though.