- Joined
- Apr 26, 2004
- Location
- The Netherlands
This thread is meant to inform anyone interested about the possibilities of a Pentium-M desktop rig, and offer a guide on how to build one, and where to get the components. The basics have been laid, what i need now is alot more user input. If you have overclocked a Dothan rig, please let me know so that i can add it to post #2. If you have made modifications to fit a non-standard cooling system, same goes for post #1. If you have questions, comments or would like to see something added, please let me know by PM to keep the thread as clean as possible.
I would like to specially thank Jimbob, Gautam, Drec, Datura and all other members that contributed to the knowledge-building around Dothan on the boards here.
Index
Post #1
1.1: Introduction
1.2: What do you need?
1.3: Where to get it
1.4: Assembling the rig
1.5: Modding the adapter
1.6: Modding the voltages
1.7: Cooling alternatives
1.8: Let the games begin
1.9: Temperature Monitoring
Post #2
2.1: OCforums member results: Index
Post #3
3.1: Links that may be useful
3.2: Parts that may be useful
3.3: Member Input
1.1 Introduction
Dothan is Intel’s codename for their latest notebook processor. It is a whole new architecture, developed in Israel. It was designed with a high IPC (instructions-per-clock) and low power usage in mind. The Dothan has a very short pipeline, similar to the Athlon64, which allows it to perform extremely well at relatively low clock speeds. Currently Dothan’s are available in speeds ranging from 1.5 to 2.1Ghz, and 400 or 533Mhz FSB. Faster models will be added in the future, together with the upgrade to 166Mhz FSB. Dothan chips come in a socket 479 ZIF (zero-insertion-force) package, and therefor aren't compatible with most desktop motherboards.
1.2 What do you need?
The socket 479 motherboards out currently use dated chipsets and have a limited feature set. Overclocking with them is possible, but not recommended since expansion and modding abilities are very limited. We will focus on the 479-to-478 adapter Asus released not too long ago. This adapter allows a socket 479 notebook chip to be used with a small array of Asus desktop socket 478 boards. These boards use decent chipsets, offer dual channel memory and a broad featureset. Overclocking options are plenty, and prices low. Current boards supported are the P4P800, P4C800 and the -E and DLX models. They come in a broad price range, so pick the one that fits your needs & budget. Next is the choice as to what chip to use. A bad thing about the Asus boards mentioned above is the fact that the PCI/AGP lock doesn't work correctly between 166 and 199Mhz FSB. Therefor, you need to boot the chip at least at 200MHZ FSB. Most Dothans will do somewhere between 2.4 and 3Ghz on high end air / water, so this is what you get:
730: 12x200 = 2.4Ghz
740: 13x200 = 2.6Ghz
750: 14x200 = 2.8Ghz
760: 15x200 = 3.0Ghz
Problem arising: booting it at 2.8 or 3Ghz may not prove to work too well. That's why, for now, we recommend either the 730 or the 740 models. Those have low multipliers and thus have the highest chance to be able to boot at 200FSB+. The 7x5 models can be ruled out for overclocking on the Asus boards, since raising the FSB to 200 means effectively doubling their clockspeed. Lower FSB may be possible on them (100 - 166Mhz), but in general they don't clock too well since they are an older revision. Therefor, the 7x0 series is your best bet.
So, the shopping list becomes:
- P4x800 Motherboard
- Asus Adapter
- Dothan Chip
1.3 Where to get it?
Speed Bump has an excellent thread going on USA where-to-buy. Availability of the adapter is slowly starting to grow, Ewiz being a large USA retailer. UK buyers can eat their heart out here. The Asus boards are commonly known and can be found at any local pc store. Dothan chips are plentiful on Ebay and alot of online shops. The adapter will cost somewhere between 40 and 50$ at the moment, a decent P4x800 board can be found for as low as 50$. Depending on the model you get, the chip will cost you between 200 and 400$.
1.4 Assembling the rig
To be able to support the adapter and chip, the Asus board needs to be flashed with an updated BIOS. See here for a list of compatible BIOS'es. Use Asus update to update your Motherboard's BIOS. You will need a standard S478 chip to complete the procedure. After you've flashed the BIOS, you can mount the adapter, the chip and the stock cooler as clearly explained in the manual provided with the CT 479 adapter. However, stock sucks, so you will want different means of cooling.
1.5 Modding the adapter
With the Asus adapter installed, two of the motherboard socket mounting holes will be (partially) covered. Jimbob_7 and i had some thoughts on that here However, modding the adapter in that way may damage it seriously. Using the Retention bracket to mount a cooling solution is the preferred option. Many waterblocks and aircooled solutions allow to be mounted using the Bracket, and, if not, some can be modded to.
For almost any serious cooling solution, you will want to get rid of the power connectors and jumpers on the adapter. This sounds more complicated then it is. First, take pliers and pull of the plastic bottom protection stuff around the pins. It should come off with a little wiggling. Then, bend the power connector 90 degrees straight onto the PCB so it will clear a heatsink. Be careful not to break any of the pins, take it slowly. Bend one of them a little further then the rest to assure that the connector will not slip off. The jumpers are a bit more tricky. Have the jumper pins removed (cut them off or remove them as awhole through the PCB). Then solder 23 and 56 onto each other on the PCB itself. Pictures of such a succesful modding can be found here and here. Be careful not to break any pins or PCB parts in the process of modding. Safest would be to stick the bottom with the pins into a layer of foam while you're busy. Also, be *very* careful to watch polarity of the power connector after this mod since the knob that will prevent it from going on wrong is non-existant.
1.6 Modding the voltages
The key to any succesful overclock is voltage. Dothans stock voltage is 1.356 max, and as we speak my chip is running 2.4Ghz solid on that. For higher clocks you may want to pinmod the chip. See here for a guide on how to do it, and a list of voltages available. A newer series of Asus BIOS'es also support Vcore changes, but they don't work on all boards and have a limit of 1.6v. Decide for yourself which method you want to use. As for Vdimm, there is some great information to be found here, and another, much simpler mod here. The latter makes vdimm equal to the 3.3v line from the PSU.
1.7 Cooling solutions
The stock cooler is small, noisy and not fitted for overclocking. Therefor, other means are required
Before you go and throw away the old heatsink, peel off the protective square shim and attach it to the CPU instead (pic) The shim is needed to protect the vulnerable core from cracking when the heatsink isn't seated properly. Mounting a HSF combination with the Intel retention Bracket is easy. However, many waterblocks and some heatsinks require the mounting holes, so you probably will need to do a bit more modding then. A list of succesful cooling mods will follow, if you have done any that aren't yet on it, please let me know so that i can add it.
I myself have succesfully modded a Zalman 6500-B CU A design to make this one work even better can be found here.
Walaka7 has modded a Thermaltake Typhoon
Gautam has modded a Waterblock and an SLK948U, i want him to take some more close-up pics tho
Eightballrj has modded a Thermaltake Big Typhoon to fit the adapter.
Note: these cooling solutions are *very* heavy, and i suggest that for transportation you take off the third-party HSF, to prevent any damage on the board, adapter or core.
Datura3 has an excellent guide going on how to install a peltier on the P4x800 and the adapter. See here for the complete story.
1.8 Let the games begin
After all this hard work of preparation, it's time to make it pay off. Boot at 201 or higher FSB to circumvent the PCI/AGP lock bug. Prime test it, which should be fine for the 730 and 740 (2.4 - 2.6Ghz on stock voltage). If not, up the voltage as neccesary. If you are confirmed stabile, you can use clockgen to increase the FSB, and EIST to lower the multiplier on the fly. Use them to determine the max FSB / CPU clock of your system, and post back with results here. If you may run into any unknown errors, please check the links listed below first. If they still can't help you, we will try our best here.
1.9 Temperature Monitoring
The Asus temperature sensor is not particulary accurate in guesstimating the chip's temperature. I've done some research on it, using a separate thermal probe mounted directly next to the CPU die. See here for the mounted sensor, and here for test results.
I would like to specially thank Jimbob, Gautam, Drec, Datura and all other members that contributed to the knowledge-building around Dothan on the boards here.
Index
Post #1
1.1: Introduction
1.2: What do you need?
1.3: Where to get it
1.4: Assembling the rig
1.5: Modding the adapter
1.6: Modding the voltages
1.7: Cooling alternatives
1.8: Let the games begin
1.9: Temperature Monitoring
Post #2
2.1: OCforums member results: Index
Post #3
3.1: Links that may be useful
3.2: Parts that may be useful
3.3: Member Input
1.1 Introduction
Dothan is Intel’s codename for their latest notebook processor. It is a whole new architecture, developed in Israel. It was designed with a high IPC (instructions-per-clock) and low power usage in mind. The Dothan has a very short pipeline, similar to the Athlon64, which allows it to perform extremely well at relatively low clock speeds. Currently Dothan’s are available in speeds ranging from 1.5 to 2.1Ghz, and 400 or 533Mhz FSB. Faster models will be added in the future, together with the upgrade to 166Mhz FSB. Dothan chips come in a socket 479 ZIF (zero-insertion-force) package, and therefor aren't compatible with most desktop motherboards.
1.2 What do you need?
The socket 479 motherboards out currently use dated chipsets and have a limited feature set. Overclocking with them is possible, but not recommended since expansion and modding abilities are very limited. We will focus on the 479-to-478 adapter Asus released not too long ago. This adapter allows a socket 479 notebook chip to be used with a small array of Asus desktop socket 478 boards. These boards use decent chipsets, offer dual channel memory and a broad featureset. Overclocking options are plenty, and prices low. Current boards supported are the P4P800, P4C800 and the -E and DLX models. They come in a broad price range, so pick the one that fits your needs & budget. Next is the choice as to what chip to use. A bad thing about the Asus boards mentioned above is the fact that the PCI/AGP lock doesn't work correctly between 166 and 199Mhz FSB. Therefor, you need to boot the chip at least at 200MHZ FSB. Most Dothans will do somewhere between 2.4 and 3Ghz on high end air / water, so this is what you get:
730: 12x200 = 2.4Ghz
740: 13x200 = 2.6Ghz
750: 14x200 = 2.8Ghz
760: 15x200 = 3.0Ghz
Problem arising: booting it at 2.8 or 3Ghz may not prove to work too well. That's why, for now, we recommend either the 730 or the 740 models. Those have low multipliers and thus have the highest chance to be able to boot at 200FSB+. The 7x5 models can be ruled out for overclocking on the Asus boards, since raising the FSB to 200 means effectively doubling their clockspeed. Lower FSB may be possible on them (100 - 166Mhz), but in general they don't clock too well since they are an older revision. Therefor, the 7x0 series is your best bet.
So, the shopping list becomes:
- P4x800 Motherboard
- Asus Adapter
- Dothan Chip
1.3 Where to get it?
Speed Bump has an excellent thread going on USA where-to-buy. Availability of the adapter is slowly starting to grow, Ewiz being a large USA retailer. UK buyers can eat their heart out here. The Asus boards are commonly known and can be found at any local pc store. Dothan chips are plentiful on Ebay and alot of online shops. The adapter will cost somewhere between 40 and 50$ at the moment, a decent P4x800 board can be found for as low as 50$. Depending on the model you get, the chip will cost you between 200 and 400$.
1.4 Assembling the rig
To be able to support the adapter and chip, the Asus board needs to be flashed with an updated BIOS. See here for a list of compatible BIOS'es. Use Asus update to update your Motherboard's BIOS. You will need a standard S478 chip to complete the procedure. After you've flashed the BIOS, you can mount the adapter, the chip and the stock cooler as clearly explained in the manual provided with the CT 479 adapter. However, stock sucks, so you will want different means of cooling.
1.5 Modding the adapter
With the Asus adapter installed, two of the motherboard socket mounting holes will be (partially) covered. Jimbob_7 and i had some thoughts on that here However, modding the adapter in that way may damage it seriously. Using the Retention bracket to mount a cooling solution is the preferred option. Many waterblocks and aircooled solutions allow to be mounted using the Bracket, and, if not, some can be modded to.
For almost any serious cooling solution, you will want to get rid of the power connectors and jumpers on the adapter. This sounds more complicated then it is. First, take pliers and pull of the plastic bottom protection stuff around the pins. It should come off with a little wiggling. Then, bend the power connector 90 degrees straight onto the PCB so it will clear a heatsink. Be careful not to break any of the pins, take it slowly. Bend one of them a little further then the rest to assure that the connector will not slip off. The jumpers are a bit more tricky. Have the jumper pins removed (cut them off or remove them as awhole through the PCB). Then solder 23 and 56 onto each other on the PCB itself. Pictures of such a succesful modding can be found here and here. Be careful not to break any pins or PCB parts in the process of modding. Safest would be to stick the bottom with the pins into a layer of foam while you're busy. Also, be *very* careful to watch polarity of the power connector after this mod since the knob that will prevent it from going on wrong is non-existant.
1.6 Modding the voltages
The key to any succesful overclock is voltage. Dothans stock voltage is 1.356 max, and as we speak my chip is running 2.4Ghz solid on that. For higher clocks you may want to pinmod the chip. See here for a guide on how to do it, and a list of voltages available. A newer series of Asus BIOS'es also support Vcore changes, but they don't work on all boards and have a limit of 1.6v. Decide for yourself which method you want to use. As for Vdimm, there is some great information to be found here, and another, much simpler mod here. The latter makes vdimm equal to the 3.3v line from the PSU.
1.7 Cooling solutions
The stock cooler is small, noisy and not fitted for overclocking. Therefor, other means are required
Before you go and throw away the old heatsink, peel off the protective square shim and attach it to the CPU instead (pic) The shim is needed to protect the vulnerable core from cracking when the heatsink isn't seated properly. Mounting a HSF combination with the Intel retention Bracket is easy. However, many waterblocks and some heatsinks require the mounting holes, so you probably will need to do a bit more modding then. A list of succesful cooling mods will follow, if you have done any that aren't yet on it, please let me know so that i can add it. I myself have succesfully modded a Zalman 6500-B CU A design to make this one work even better can be found here.
Walaka7 has modded a Thermaltake Typhoon
Gautam has modded a Waterblock and an SLK948U, i want him to take some more close-up pics tho
Eightballrj has modded a Thermaltake Big Typhoon to fit the adapter.
Note: these cooling solutions are *very* heavy, and i suggest that for transportation you take off the third-party HSF, to prevent any damage on the board, adapter or core.
Datura3 has an excellent guide going on how to install a peltier on the P4x800 and the adapter. See here for the complete story.
1.8 Let the games begin
After all this hard work of preparation, it's time to make it pay off. Boot at 201 or higher FSB to circumvent the PCI/AGP lock bug. Prime test it, which should be fine for the 730 and 740 (2.4 - 2.6Ghz on stock voltage). If not, up the voltage as neccesary. If you are confirmed stabile, you can use clockgen to increase the FSB, and EIST to lower the multiplier on the fly. Use them to determine the max FSB / CPU clock of your system, and post back with results here. If you may run into any unknown errors, please check the links listed below first. If they still can't help you, we will try our best here.
1.9 Temperature Monitoring
The Asus temperature sensor is not particulary accurate in guesstimating the chip's temperature. I've done some research on it, using a separate thermal probe mounted directly next to the CPU die. See here for the mounted sensor, and here for test results.
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