Centrino is Intels mobile chipset, at its heart lies the Pentium-m series CPU. These run (compared to their P4 brothers) slower and a LOT cooler runing on just 1.35v at stock. The Dothans have a TDP (Thermal Design Power) of just 21w (for 400 fsb chips) and 27w for the 533 Sonoma cored chips. This compares to around 100w average for the standard P4 and A64 chips, similar differences in heat output emerge when the cpu's are loaded. The P-m's boast 2mb L2 cache (as found on Intels Extreme Edition CPU's) and are in fact based on a revised version of the Pentium 3 core, with added SSE2 instructions and a 90nm build process. The Dothans also feature Intels Speedstep technology, which allows them to throttle back when idle. So, these chips are cool, run fast (multiply clock speed by 1.9 to get an estimation of the equivalent P4, this isnt 100% true, but seems a fair estimation) why arent they available for desktop use? Well now they are. Certain motherboard manufacturers have launched desktop versions of the mobile chipset (the 855 supporting single channel and 400 fsb and a board based on the 915 chipset, supporting DDRII and PCI-e) Asus has also developed a nifty convertor allowing the 479 P-m CPU's to run on a normal 478 socket motherboard. Asus has also provided bios support for some of their 865/875 and 915 chipset based motherboards. With a bios flash, and the CT-479 (Asus's adapter) you can happily run a Pentium m cpu on a desktop motherboard. Brilliant! The CT-479 Adapter in all Its glory! After noticing a cheap 1.5ghz chip or sale, the tempation to build a Dothan based machine was too great. A week later, an Asus P4P800SE motherboard, the CT-479 adapter and the Dothan arrived. Bundled with the CT-479 is the Convertor itself, a comprehensive instruction manual (though its hard to go wrong), a power adapter for the convertor (as it cant draw all of the power it requires from the CPU-socket) and a cooler. The first thing that struck was the size of the cooler. Its tiny... Here it is, compared to a SE T610 The coolers base sports a small square of thermal compound, and a foam shim to protect the fragile core of the cpu. Installation is simple, simply place the convertor into the mothboards cpu socket, and close the retention clamp as you would for a cpu installation. Then, insert the CPU into the convertor, and turn a screw to lock the cpu into place (this is the common mounting method for P-m cpu's) finally, install the cooler using the supplied mouting clips. The cooler mounts to the standard P4 mount meaning a standard P4 cooler (with modification) could easily be applied. This could however be considered overkill. Thats it, the machine can be booted and used as normal. The only problem with building such a system from "new" is that a bios flash is required for the motherboard to recognise the cpu. Those without a P4 cpu available to allow them to bios flash have 3 options, hotflash, order a pre-flashed chip from a site such as bad flash, or buy a cheap P4 to allow flashing. And here it is, a Pentium M in windows, on a desktop pc! Now that its installed, how does it run? Stock system, bios settings left at default. CPU @ 1.5ghz, 100*15 (400mhz QDDR) Memory at 133mhz (3:4 divider) 2.5,2,2,6 (spd settings) 4*256mb, 2*OCZ EL, 2* Elixir Well at stock, Super Pi to 1 million places was a rather unpromising 50 seconds, with winrars benchmark compressing 24 mb in 60 seconds. Not overly quick, but not too bad for a cpu at 1.5ghz and 100fsb. Now onto overclocking As this is a 400 fsb cpu, the older revision Dothan core overclocking suffers somewhat compared to the newer chips. The high multiplier also limits the overclock somewhat. Achieving an FSB of 200 appears to help these chips overclock much further, especially since their multiplier can be dropped via software. The bios (1009 beta) gives a few options, firstly a memory divider, front side bus control, AGP and PCI frequencies, as well as the usual Vdimm,Vcore adjustment and vAGP. Vcore is adjustable from 1.2 -> 1.6 which is ample. From the stock fsb of 100, a raise of 62mhz to 162 was achieved. This was NOT the limit of the chip by any means, there appears to be a "wall" with these 400fsb variants at between 160 and 200 fsb. It is not known why this occurs as of yet, but hopefully multiplier adjustment in bios will help. The cpu required a vcore increase of 0.15v to 1.50 to attain a clockspeed of 2429 mhz (162*15) this was achieved using the stock cooler, with a maximum load temperature (measured via asus probe) of 38°C. Memory was run on a 4:5 divider (maximum available with this bios) resulting in a 202mhz bus speed. Timings were eased from the previous 2,2,2,6 to a more modest 2.5,3,3,5. Increasing the FSB anymore than this resulted in either no boots, or instability in windows or during the Super-Pi tests. More vcore didnt help, still need to look into multiplier adjustment via software to search for higher FSB. Performance at these speeds was stunning. Super-Pi ran the 1m test in a stunning 31.344 seconds, which for a 2.4ghz cpu, at such a low FSB is amazing. For comparison, a 2.6ghz clocked A64 system, at 260*10 ran this test in 32.937 seconds. Winrar on the other hand did not fare as well. At overclocked speeds, 34mb in 60 seconds was the best result. Its still a mighty fast time for a 2.4ghz cpu, but it doesnt come close to the mighty power of the A64. I'll run other tests over the coming days, and see how well the system fares in games and in general windows use. So, to a conclusion. Cost initially, well the system has cost me a little over 150 GBP to put together (103 for motherboard and CT-479 50 for CPU and a further 45 for a new PSU, but this can be discounted). With the rest of the components being used from previous builds. The CPU was second hand, which greatly reduced costs, a new 730 533 fsb chip weighs in at around 140 GBP. However, considering, with a small amount of patience, in some applications this chip can match or beat an FX55 its worth the price. You could also look to ebay for a bargain, as people update the chips in their laptops. However, try and stick where possible to the 533 fsb versions, especially the 730 and 740 as these have the most favourable multipliers for overclocking. The FX series as well as the standard A64 and Pentium 4 (5/6xx series and the EE's) are fast out of the box. The M's need to be overclocked to realise their full potential. But, as ever there is always a risk that a cpu won't overclock well. Most of the M's seem to do 2ghz with ease, many break 2.5 without a problem. However for those wanting a fast system without overclocking, it may be wise to look elsewhere, or to consider and expenisve, higher stock speed chip. The performance:cost:noise ratio of these chips is simply stunning. At 2.4ghz and a low fsb for a chip for match and beat processors 2 times their speed is amazing. Intel really do have a simply stunning processor in the Pentium-M. It seems they plan to focus more along its lines, as the recent announcment of their abolishment of the netburst arcitecture indicates. Onto the quesion, should you go and buy one? Well thats up to you to decide. For more information, check out the Intel section on Xtremesystems.org for numerous threads on this subject. I'll try and update this post/thread over the coming days with more benchmarks and real world performance figures. If there are any particular tests you want running, feel free to ask for them Further pictures can be found here
Very impressive. I'm really hoping that we'll see boards using the mini-itx or nano-itx formfactor (the VIA EPIA sized ones, 17cmx17cm and 12cmx12cm respectively) supporting the s479 and a desktop chipset for good memory bandwidth. Could really revolutionize the super-small form factor setups, and in any case is great for low-power-consumption desktops.
Hopefully Intel will get a clue and release a desktop architecture based on the Pentium M's power saving features-and stup using stupidly high heat output transisters on parts running at 6 Ghz +...
Nah the single channel version of the 479 supporting chipset is 479 Quick results in, coupled with a 9500NP sofmodded to pro (8 pipes) stuck in a 01 run just over 20k today. Insane for a 2.4ghz cpu and 162 fsb (ran 1:1 this time)
That Asus adapter so far is only proven on Asus motherboards; theoretically it will work on some others, but many others will probably not support them.
The sooner someone releases an i915 board with MPGA479, the better. I seriously need a Pentium M for some fun.
Aopen have just announced a full ATX based on the i915G + ICH6. It has stuff like component out and dvi out and even the wierd jap dvi connector, so i dunno if we'll see it in the EU that soon.
am i right in saying that the 730,740,750 etc are the 533fsb versions whereas the 735,745 etc are the 400fsb versions? would it make much difference on what mobo you use? would a heatsink just need some more space in the vertical direction, to compensate for the height of the adapter? ta erm, also, where did you find the adapter? fleabay?
i hear the performance of the board is poor compared to getting it done with the adapter and old skt 478 board....im most impressed with intel for having created a cpu that makes buying a skt 478 board a worthy investment... bit behind on the whole intel side of things, does ICH5R just mean native sata support?
You are indeed Nope, all will work just fine in all supporting boards You can use any standard heatsink on the CPU, just needs the mouting modifying, as the cpu sits higher than a standard P4 cpucity.co.uk kustom also sell them, and theres another UK e-tailer. Cant remeber who tho. Toying with getting a 730, but at ~ 130 quid pushes the cost of things a little too high Cant decide... Someone make the decision for me!
were is the cheapest you have seen them? ebuyer looks ok, but then again im still undecided on the mobo to go with...do any of the compatible asus boards come with ncq?
