With Intel's tick-tock release model, there is a new CPU generation released each year. Tick is an old architecture on a smaller process (like Ivy Bridge in 2012), while tock is a new architecture on an existing manufacturing process (like Sandy Bridge in 2011). Intel's new 4th generation Core CPUs are based on a new Haswell architecture, which is more efficient at utilising 22 nm process than Ivy Bridge. It also comes with another boost to Intel's integrated graphics, especially in top BGA and laptop parts with Iris Pro 5200 with additional eDRAM.
When getting Haswell CPUs for desktop PCs, the new motherboards with 8 series chipsets and LGA-1150 socket. Among the improvements from 7 series is the native support for 6 USB3 ports and 6 SATA3 ports. The support for legacy PCI is gone, but there will be motherboards which will use additional chips for legacy support. C1 stepping chipsets may lead to depowering bug with some USB3 devices. C2 stepping chipsets, which are shipping and BGA configurations don't exhibit any problems with USB3 devices.
On desktop, the socketed versions of Haswell CPUs don't offer as much excitement as previous tocks. The benchmarks of top mainstream part – i7-4770K don't differ much from the March preview of engineering sample. The memory bandwidth bug has been fixed and it performs very well with fast DDR3-2400 memory. The best gains over Ivy Bridge on the same clocks are in multi-thread floating point workloads, where Haswell manages to get up to 20% more performance while also being a bit more power hungry. In many other workloads (including gaming with a dedicated GPU) the improvements are less than 10%. Room for overclocking also doesn't seem any better than Ivy Bridge. With all that, Haswell doesn't look like a tempting upgrade for those who are using Sandy Bridge or Ivy Bridge CPUs, but Intel's incremental improvements add up to something more tempting for those who are using even older CPUs.
Haswell was designed for better power consumption and thus it is most interesting for use in laptops, compact desktop PCs and tablets. The impressive performance of Iris iGPU parts is also a good bonus for cases where power consumption (linked to battery life) and size is an issue. Intel added a lot of power saving features in both Haswell CPU and platform, allowing it to use lower power modes and switch to them in a faster and less user distracting way. Thus laptops using it will either give us a longer battery life or will trim their weight and size. While HD 4600 iGPU (20 EUs) is only a small improvement over HD 4000 (16 EUs), HD 5000 and Iris with their 40 EUs are very impressive iGPUs. Anandtech has benchmarked Iris Pro 5200, which manages to get quite close to mid-range Nvidia's GT 650M laptop graphics card. It is the most powerful iGPU at the moment, capable of playing most modern games at 1366x768 at medium quality. However it isn't cheap and for gaming on the go laptops with more powerful graphics card may end up cheaper.
Overall, Haswell is the architecture which aims more at power usage and compact platforms than on increasing the top performance. The gains on desktop quad-cores are lower than during previous architecture launches, but they are enough to retain lead, as AMD CPUs performance is still behind in most tasks. In laptops the more efficient power usage and better iGPUs are very helpful. Finally, in tablets and hybrids, Haswell may become a very serious push for x86 and ARM contender. Those devices may make the dual-faced nature of Windows 8 much more useful in the future than its current sorry state on desktops and laptops.
Review roundup:
Anandtech
Anandtech Iris Pro review
HardOCP
Tom's Hardware
Overclockers.com
Techreport i7-4770K and Iris Pro review
