TheOverclocker Issue 24 | Page 31

Bridge and Nehalem for example. The next generation of INTEL products will be a tick essentially bringing the Haswell microarchitecture to 14nm. The fifth generation of INTEL Core products we know as Broadwell. The next Tock, after Broadwell in 2014 is Skylake, scheduled for 2015 release. So what is new about Haswell? From a practical overclocking point of view, not much, however from an engineering and focuson-overclocking perspective, a lot has changed. The most dramatic novelty in Haswell is moving a large chunk of the VRM from the motherboard onto the CPU die - that is integrating it into the CPU package. This is quite an impressive feat from a design perspective. Many people, enthusiasts such as you and us, feared that INTEL’s taking over the control of the VRM design would limit the overclocking capabilities in a similar fashion as integrating the clock generator limited overclocking on Sandy Bridge. Fortunately, that is not the case. Apart from the VRM implementation, Haswell introduces a couple of new instruction sets, an on-die eDram and a variety of improvements for overclocking. HASWELL FREQUENCY CONTROL - THE BASICS As the main structural parts of the Haswell micro-architecture are quite similar to those of Ivy Bridge, we can distinguish mostly similar sections on the CPU die: - Core(s) - L1, L2 and L3 cache - Ring bus - System Agent - Integrated Memory Controller - Integrated Graphics Processor - Edram IC Simply stated, the Ring bus connects the various sections of the silicon, just like on Sandy Bridge. The L1 and L2 cache are still exclusive to the CPU cores, meaning each CPU core has its own L1 and L2 cache, and the larger L3 cache is shared with all cores as well as the internal graphics processor. The ring bus serves as a data bus for transferring data around the CPU die. New in Haswell is the introduction of an on-die IC called eDram, [which according to INTEL provides significantly more bandwidth and reduced access latency compared to regular DDR3 and will be used to support the integrated graphics processor for performance purposes]. Issue 24 | 2013 The OverClocker 31