Legit Reviews

Pentium eXtreme Edition 840: Long Awaited Processor with Quite Predictable Performance

... The main problems of new Intel processors spring from the approach to their design: if the entire concept consists in placing two almost independent CPUs on a single die, you can hardly expect from this CPU a compact size, low heat dissipation, and low power consumption . That's exactly what happened: Pentium eXtreme Edition 840 die has the surface area of 206 square mm, it contains 230 million transistors, and it consumes 130 W. Pay your attention: even Intel admits in its documentation that the CPU power consumption specified is not the maximum value: "...Intel recommends that complete thermal solutions designs target the Thermal Design Power (TDP) indicated in Table <...> instead of the maximum processor power consumption...".

The positive point: the new Pentium XE 840 got the full set of the latest functions that come together with its core (doubled Prescott E0): EM64T support (counterpart of AMD64), Execute Disable Bit (XD), and Enhanced SpeedStep. The negative point: with all its impressive characteristics, the clock of a single core is rather low (for these days, of course): 3200 MHz. And that's eXtreme Edition, regular desktop dual core processors (which will be called Pentium D) will have just 2800 MHz (Pentium D 820).

Thus, the Intel concept currently offers a choice between two mutually exclusive options: either clock (Pentium 4 eXtreme Edition 3.73 GHz, Pentium 4 570J, Pentium 4 660), or multiple cores (Pentium D 820-840, Pentium eXtreme Edition 840). The multi-core Pentium D currently differs from the Pentium XE with the same Processor Number only by disabled Hyper-Threading in Pentium D, so the system will detect it as two processors, while Pentium XE will be detected as four processors (2 physical cores + Hyper-Threading for each core). Dual core processors do not yet support the fastest FSB (its bandwidth is 1066 MHz), all of them, including Pentium eXtreme Edition, do with the old 800MHz bus.

Judging from the above said, the following assumption seems logical: Pentium 4 eXtreme Edition 840 performance at best must be identical to the system based on two Xeon proccesors supporting Hyper-Threading, with a Prescott-like core, 800MHz FSB, 1MB L2 Cache, and 3.2GHz clock. That is Intel Xeon 3.2 GHz for Socket 604, for example, with sSpec Number SL7TD or SL7PF. There are no reasons to expect more from this processor. Unfortunately, we don't have an SMP system on these Xeon processors so far in our lab. So, today we can just look at the gain from the second core by comparing Pentium XE 840 with Pentium 4 540J.