For Overclocking, DFI offers several possibilities for this motherboard, all with a low energy consumption configuration. So it is basically impossible to increase the CPU voltage beyond 1.34V and increase the memory power input. Overclocking capacity is then restricted to your components standard frequency.
As for the bios, the latest X86F0.bin of The_Mad is much more advanced for overclocking than the official bios:
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CPU Clock :This is the processor FSB: 100 MHz to 133 MHz for the last Pentium M supported by this motherboard. In practice we were able to reach 175 MHz with our processor. To obtain this excellent result for a chipset only certified at 100 MHz by Intel, we reduced the coefficient.
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Async PCI / AGP Clk :Several options are available to adjust the AGP and PCI bus frequency, with of course the option to keep the bus to 66 and 33 MHz for any FSB. We noticed that with ATI’s board, in keeping the bus to 66 and 33 MHz it doesn’t seem to work correctly. It’s therefore imperative to resolve this issue by choosing the right ratio amongst the ones available:
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Memory Ratio : It is the DDR:FSB ratio, This ratio can be 1:1, 4:3 or 5:3. The last value allows you to have memory clocked at 133 or 166 MHz (DDR266/333) respectively, with a FSB 100.
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CPU Ratio (FID) :This is the processor multiplying coefficient. It may not be increased beyond the standard processor value, but it may be reduced to have a higher FSB, for example.
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CPU Ratio (VID) :This is the CPU power input. There again it is impossible to increase it beyond the standard value, but it may be reduced to Overclock the processor. It won’t be that useful, though, as we already know it’s possible to silently cool down the processor.
In practice we were able to reach 2.5 GHz with our Pentium M 755 2.0 GHz. To do so, we chose the following parameters: FID 17x, FSB 147 MHz, a 4:3 memory ratio and DDR at 196 MHz. We also also briefly tested a Pentium M 745 (1.8 GHz) for overclocking. The processor reached 2.4 GHz in 16x150 with memory at 200 MHz (DDR400).
These Overclocking results are good overall, but not extraordinary. They are of interest if we consider that they were obtained with a silent configuration, a simple cooling system and without electrical tension increase. With a tension increase, not currently possible with Pentium M desktop motherboard (without hardware modifications), it suggests we would be able to reach 2.8 GHz frequencies! Even better the last Pentium M FSB533 based on a new chip revision seems to reach higher overclocking. Our colleagues from
x86-secret reached 2.7 GHz with a 2.13 GHz version without a tension increase.
FYI, here are performances reached in overclocking with several frequency fsb/memory combinations. Results were measured with Unreal Tournament 2004, which like many games is very dependant, in addition to processor frequency, on these parameters:
The performance gap between the best and worst environment is 18%. As you may have noticed memory speed seems to have more influence than FSB speed (this is consistent with the bus and theoretical frequency speed). The best result here is FSB 150 MHz and 200 MHz for the Corsair XL (memory timing of 2-2-2-5) DDR-SDRAM. The FSB frequency can be directly adjusted under Windows with
SetFSB or
ClockGen.
Aopen, a direct competitor, also offers software to change the coefficient, the FSB, and also to activate the SpeedStep and directly regulate the processor fan speed. It’s just unfortuneate that DFI hasn’t developed identical software to make this modification, and we have to use software developed by individual users to adjust these functions (except for the fan rotating speed which doesn’t work with SpeedFan for the moment).
For the time being, it isn’t possible to configure a CAS Latency with bios other than the one specified in the SPD memory module. Corsair only indicates one CAS 2 in the 3200XL SPD, so it is almost impossible to use them in CAS 2.5 (the CAS 3.0 isn’t supported by the chipset). This isn’t that important as we don’t need to reach high frequencies, but it’s still a little disappointing.
Finally, in terms of power consumption, we measured, the entire configuration power consumption (motherboard, 2x512 MB of DDR-SDRAM, Radeon 9200, 1 Raptor) with Prime95. Measurments were made from the electrical plug, so the real configuration power consumption is lower as power supply efficiency is 70% to 80%. Here are the figures obtained:
- Pentium M 755 2.0 GHz : 78 Watts
- Pentium M 755 Oveclocked at 2.4 GHz : 81 Watts
The initial power consumption is very low and overclocking doesn’t change this result much because of the stable electrical input. In order to compare, an identical configuration with a K8N Neo2 coupled with an Athlon 64 has the following power consumption:
- Athlon 64 3200+ 90nm : 110 Watts
- Athlon 64 3500+ 90nm : 113 Watts
- Athlon 64 3500+ 130nm : 130 Watts
This configuration consumes less power than one based on an A64 90nm, which so far has been a configuration that has consumed the least for desktops.
The test
The Pentium M has low power consumption and heat dissipation, and can be easily and silently cooled down even when the processor is overclocked. So how about performance? We conducted our usual processor tests:
Tests were made on the following platform: - Socket 479 : DFI 855GME-MGF
- Socket 775 : ASUSTeK P5AD2-E Premium
- Socket 754 : MSI K8N Neo (nForce3 250)
- Socket 939 : MSI K8N Neo2 (NVIDIA nForce3 250 Ultra)
The other configuration components are:
- 2x512 MB DDR-2 533 Corsair with timings of 3-3-3-8, Socket 775
- 2x512 MB DDR-400 Corsair with timings of 2-2-2-8, Socket 939 & 754
- 2x512 MB DDR-333 Corsair with timings of 2-2-2-8, Socket 479
- NVIDIA GeForce 6800 GT PCI-E Socket 775 (ForceWare 66.81)
- NVIDIA GeForce 6800 GT AGP Socket 939 (ForceWare 66.81)
- Western Digital WD800BB
- Western Digital Raptor WD740GD
- Windows XP SP1 French
You will notice that we integrated figures from overcloked processors such as the Pentium M 2.4 GHz (16x150, DDR400) and 2.5 GHz (17x147, DDR392). We don’t usually do this, but as the Pentium M has a great overclocking potential at initial power input and without the inconveniences of increased heat dissipation, we thought it would be of interest to include these figures. (Overclocking was obtained when slightly pushing the processor and without power increase).
Of course it’s possible to overclock other processors, but several architectures are already well represented in the benchmark like FX-55 at 2.6 GHz for the Athlon 64 or the 570J 3.8 GHz for the Pentium 4.
For more information we also looked at how the Pentium M dealt with WM9 video decompression even if we don’t usually do this in tests. We used the resource heavy 1080p Step Into Liquid version (
download it here. The Pentium M has the raw power necessary from 1.8 GHz to insure the playing of this video with a fluid image and a good frame rate, whereas with the Pentium 4 a « simple » P4 520 (2.8 GHz) is enough (processor CPU use is distorted by HyperThreading and so this figure isn’t really that interesting). The Athlon 64 is also able to correctly read this video in 1.8 GHz.
Of course the same video in 720p is read without problem with a Pentium M 1.6 GHz and a processor use of 50 to 60%. Also, in the following weeks the Radeon X700/X800 and GeForce 6600/GT, 6800 (NV41) Windows Media Video should be activated, and it will be possible to play very heavy WMV files even with a less powerful CPU.
