The guys over at ChinaDIY have managed to attain an engineering sample of a Core i5 Haswell CPU. It is unknown which model it is, but the specifications are known.
The CPU is a quad-core part without HyperThreading, as was the case with (most of) the Ivy Bridge i5 parts. The CPU's base clock speed is set at 2.6 GHz, and the Turbo Boost 2.0 enables it to reach a frequency of 3.0 GHz. This is under a TDP of 84 W. (The CPU-Z has a bug; hence it says 83 W.) What's more interesting, though, is the idle clock speed. While Ivy Bridge chips only clocked down to 1,600 MHz, the Haswell chips should clock all the way down to just 800 MHz, which should really save on the power bill if you were to leave the computer running idle much of the time. Furthermore, the CPU packs 6 MB of L3 cache along with an HD 4600 graphics part. Beyond this, the Haswell chips should also feature better overclocking abilities. While the highest overclock is not what we're talking about, the CPUs will support BCLCK and FSP adjustments as well as overclocking the memory up to 3,200 MHz.
Here are the shots of the benchmark results; enjoy the trip. Do consider though, it still remains unknown which version of the Haswell i5 CPU this is. Considering the clock speeds, it is likely that this is not the flagship "i5-4570K," but rather a lower model.