DFI 855GME-MGF and Pentium-M Dothan Desktop Performance

Here's a quick run-down of the Pentium M "Dothan" core processors available at this time.  We used a Pentium M 755 for testing with the new DFI 855GME-MGF motherboard.

The Intel Pentium-M Processor Dothan core in socket 478

Intel Pentium M processors 765, 755, 745, 735, 725, 715, 738 Low Voltage and 733/723 Ultra Low Voltage. •Speeds 1.50GHz - 2.10GHz • Supports Intel Architecture with Dynamic Execution • On-die, primary 32-kB instruction cache and 32-kbyte write-back data cache • On-die, 2-MB second level cache with Advanced Transfer Cache Architecture, 3-way set associativity and ECC (Error Correcting Code) support •Data Prefetch Logic • Streaming SIMD extensions 2 (SSE2) •400-MHz, source-synchronous FSB •Advanced power management features including Enhanced Intel SpeedStep technology •Micro-FCPGA and Micro-FCBGA packaging technologies •Manufactured on Intel's advanced 90 nanometer process technology with copper interconnect. •Support for MMXTM Technology and Internet Streaming SIMD instructions •The processor's data prefetch logic fetches data to the L2 cache before L1 cache requests occurs, resulting in reduced bus cycle penalties and improved performance.
Pentium M Right, Pentium 4 LGA775 Left	Pentium M Right, Pentium 4 Skt. 478 Left

As you can see, although this is a 478 pin Intel processor socket, the Pentium M pin-out is in fact keyed differently than a standard Pentium 4 socket 478 CPU.  And the two sockets are not compatible.  The internal architecture of the Dothan core Pentium M processor is held very guarded by Intel.  In fact, it is not known how many stages Dothan's pipeline has but it is rumored to be somewhere in the neighborhood of 12.  This explains the processor's ability to have significantly better overall throughput clock-for-clock versus the 31 stage pipeline in the Pentium 4 Prescott core. 

What we are very much aware of is that this new Pentium M core has 2MB of full speed, on chip L2 cache, the same amount of L3 cache that Intel incorporates on their Pentium 4 Extreme Edition CPUs.  Intel has recently come to adopt larger cache sizes for all of their future processor P4 designs as well, due to the obvious performance benefits in gaming and multimedia applications. 

Finally, what is truly amazing here is the processor's power consumption profile or "thermal design power" as Intel likes to call it.  Thermal design power is the maximum power that the processor's thermal solution (in this case the HSF on the CPU and surrounding ventilation in a chassis) is required to dissipate without exceeding the processors maximum junction temperature, in this case 100^oC.  By stark contrast a Pentium 4 Extreme Edition 3.46GHz CPU, which dissipates over 110 watts TDP (thermal design power), and can only reach a maximum junction temperature of 66^oC.  With a TDP of only a mere 21 watts (only 5 watts for the Ultra Low Voltage versions), you can imagine just how small and quiet a Pentium M heatsink and fan combination can be, while still providing more than adequate cooling.