Just to clear up some confusion: Intel actually has 3 different lines of Pentium chips right now:
1. Pentium 4
or "P4" is a desktop chip. The new ones come with HyperThreading and are allso known as "P4HT
". Power requirements of CPUs are proportional to the square of their voltage, and the latest generation of desktop chips use low voltages: 1.5V in the case of the P4. This allows them to be used in laptops with acceptable battery life. Compare this to the best laprtop processor of a few years ago, the original P3-M, which used 2.3 Volts (note that this is *not* the P3's used today - modern versions of the P3 are 'ultra-low voltage' and use under 1 volt). Check here
for a discussion of processor voltage.
2. Mobile Pentium 4
is the version of the P4 designed for laptop use, also known as the "P4-M
". The key feature of the P4-M is its ability to run on a different range of voltages, sacrificing processor speed for energy efficiency. The P4-M runs between 1 and 1.3 volts, and runs at the same speeds as a P4 (the 533 MHz FSB versions, up to 3.06), with the same instruction set and operations per cycle, so a P4-M at a given speed is just as fast as a P4 at that speed,
is a different
chip than the P4, with a different architecture, and can perform more operations per cycle, so even though its clock speeds are slower (0.9 - 1.7GHz), it can process as fast as a P4. This processor is part of the Intel Centrino
package, which also includes wifi, so this is often referred to as a Centrino processor, even though it can be used without the Intel wifi, which prevents it from being called Centrino (as that is a specific marketing label for the whole package). The P-M processor, like the P4-M, can run slower using less voltage to conserve battery power, and its operational range, depending on base speed, is 0.84 to 1.5 volts.
Ok, so a P-M supposedly can perform 1.8 times the operations per cycle as a P4, which means a 1.7 P-M runs just as fast as a P4-M 3.06, which runs just as fast as a P4 3.06. Right?
Well, not quite. First, the 1.8x figure is marketing hype, you need to check out actual benchmarks of one processor against the other. 1.8x is optimal
performance, typical performance, while it does let the P-M run perform equivalently to a P4-M with a higher clock speed, isn't a full 1.8x multiple. Second, P4HT will blow away a P4, P4-M, or the equivalent P-M in any situation involving multiple threads or applications running concurrently, thanks to its improved multithreading capability. Given that that covers 80%+ of typical computing situations, including all
complex games, the P4HT has a huge advantage.
Then, there are considerations other than the processor. The latest P4HT chipsets also support 800 MHz FSB and dual-channel memory, features that simply aren't available for the P-M or P-4M. For reference, the P-M uses a 400 MHz FSB and the P4-M uses a 533.
So no question that the P4HT wins on speed. But also no question that the P-M wins on battery life and less heat production. The P4-M seems to be being phased out in favor of the P-M, which makes sense, as the P-M is a much better design for portability.
So where the P-M shines is in the ultraportable category. The physical chipset to install it is smaller, lower power consumption allows a smaller battery, and lower heat production allows a smaller cooling system. Put that together and you can come out with a really tiny machine.
Sager is known for the other end of the spectrum - powerhouse desktop replacement notebooks. Sagers tend to be broad and deep to accomodate large (15"+) screens and thick to house multiple optical drives and lots of features. Throw in a cooling system to handle a desktop P4, and you have some of the largest, heaviest notebooks on the market. But, with P4HTs, some of the highest-performing ones as well.