As a “tock” phase CPU, Haswell has a new microarchitecture. Much of the focus on this new architecture (arguably most of the focus) was on lowering space and power requirements, as Intel sees tablets, ultrabooks, and low-power all-in-one designs as being very important moving forward. That’s not to say they’re ignoring the desktop market, but reading the Intel press deck, one certainly gets the impression that it’s not their main focus. For example, one of the options for the mobile device segment is a hybrid chip with both a Haswell core and the PCH (platform controller hub) mounted on a single ball-grid array package. Intel brags about “unprecedented” increases in battery life, “unprecedented graphics in an ultra-thin form factor”, and the applicability of Haswell mobile CPUs in “thin and light” platforms.
There are a few bones thrown to desktop users. One desktop CPU feature enthusiasts will appreciate is the return of base clock tuning. Starting with Sandy Bridge, the classic overclocking technique of raising the system base clock become almost impossible, since the new design derived most other system clocks from the base clock. So by raising the base clock, you also raised the clocks used for other parts of the CPU as well as its communication with the rest of the system, and this meant that raising the base clock more the 3 or 4MHz would make your rig crash. Although Intel’s description of this new “B-clock tuning” mechanism is void of any technical details, the claim is that you can “…achieve high core, graphics and memory frequencies by independently raising your clock speeds without impacting other system components”. While not as versatile as multiplier overclocking, base clock overclocking should enable users of non-“K” series CPUs to finally get some extra performance.
The Haswell die layout looks almost identical to the Sandy Bridge and Ivy Bridge dies. The actual die size is up a little over the 3770K, at 177mm2 as opposed to 160mm2. Intel quotes the transistor count as 1.4 billion in either case, which seems odd given the increase in iGPU execution units. Although the die size is larger, the LGA1150 package desktop CPU is the exact same size as the LGA1155 desktop CPU. The only visible difference is a slight repositioning of the locator notch, so you hopefully won’t be accidentally installing a CPU in the wrong socket.
The Z87 Platform Controller Hub
The Z87 (Intel has dropped the “Express” designation) chipset, code-named Lynx Point, is the new Platform Controller Hub for the desktop Haswell CPUs. Speaking of “technical diagrams that look almost the same as the technical diagrams for the previous generation product”, here’s Intel’s block diagram of a Haswell/Z87 system:
This diagram looks very similar to the Ivy Bridge/Z77 diagram. The main differences are:
Support for PCI slots is gone, even as an option. It’s PCI-E all the way. All you people still using your old Sound Blasters: it’s time to move on.
We get two more USB 3.0 ports and two more USB 2.0 ports.
We get up to six SATA 6Gb/s ports, up from two on the Z77.
None of this is earth-shaking, but represents instead a continual refinement of the capabilities we originally saw in the Z68/Sandy Bridge platform.