how to tell from the cpu model?
Any numbers with M, Q, E, H, U and Y
suffix are CPUs from Haswell line
Any numbers with Z and N
prefix are CPUs from the Silvermont (aka Bay Trail) line
Examples:
Core i3 4010U (Haswell) - 2 core, HT
Pentium 3561Y (Haswell) - 2 core, no HT
Celeron 2955U (Haswell) - 2 core, no HT
Pentium N3520 (BT) - 4 core, no HT
Celeron N2840 (BT) - 2 core, no HT
Atom Z3770D (BT) - 4 core, no HT
Do note that Haswell Celerons & Pentiums are of different calibre than BT's Celerons & Pentiums. The latter are less powerful and consume less power than the former.
I am using the Dell Inspiron 11 3000 with the Pentium N3530, swapped stock HDD to 840 Evo and swapped stock 4GB RAM to 8GB. It serves fine as a media consumption device and regular web browsing. The limitation after you've upgraded the RAM & HDD is the onboard graphics. It's a little on the sluggish side when loading webpages with lots of high-res pics.
Then again, I'm using Firefox to browse which renders the page first before you view unlike Chrome which feels faster since you view as it renders. Performance is also fairly dependent on how you tweak the power settings. Setting the cooling policy to Active helps with throttling and maintaining battery life over the long-term
Interestingly, I find youtube playback is more smoother using a Metro Youtube app rather than directly within your normal browser.