Intel Pentium D 805 - Dual Core on a Budget

Power Consumption

As always, we measured power consumption of the entire system at the wall outlet. First up is power consumption with the test system at idle. Here AMD's Cool 'n Quiet and Intel's EIST really come into play and do their best to reduce power consumption:

As you can expect, based on the old 90nm Smithfield core, the Pentium D 805 isn't exactly the coolest running chip on the block. In fact, the Athlon 64 3000+ consumes less power under full load than the Pentium D 805 does with both of its cores idling. Note that the higher power consumption on the two Opteron parts is because Cool 'n Quiet would not work with the Opterons on our test platform.

The picture doesn't get any prettier under full load. If you're expecting the Pentium D 805 to be a cool running, quiet chip, you're going to be sorely disappointed. If power consumption matters to you then you're far better off with a Pentium D 900 series or an Athlon 64 X2.

Looking at the long-term prospects, power costs money, so how long will it be before the lower power X2 3800+ reaches the break-even point? If we go with a typical $.10 per kWHr, the X2 3800+ consumes 37W less at idle and 48W less at full load. If that seems like a lot of power initially, it actually only works out to $32-$42 per year, running both systems 24/7. That means you're looking at a minimum of four years to reach equivalence in price+power. What about the 920 versus 805 power costs? The difference there is even less in terms of power use, so even at full load you're looking at $16 per year, or seven years to reach the break-even point.

Of course, you can't just look at power in most instances. The X2 3800+ will offer you faster performance during its lifetime, so it definitely warrants consideration. Lower power, lower heat, lower noise, and higher performance are all nice things to have.

Note: Pentium D 820 numbers were excluded from the power comparison due to technical difficulties with our test platform at the last minute. Based on the data here, you can expect it to consume more power than the Pentium D 805.