X61 with quad-core should be feasible.
Posted: Tue Feb 10, 2015 8:43 pm
I ran a few tests and did some calculations, and an X61 with a quad core should work out pretty well. A T9900 has been found to work, just barely, in an X61, so I used that as a baseline reference of the maximum power consumption/heat output that could possibly be supported by an X61. I have a T9900 in my T500 and its lowest voltage at stock clocks while remaining 100% stable is 1.1 volts. I don't know how many watts it is using, but that doesn't matter since the relative difference works out just fine as well. A stock Q9000 operates at 2Ghz, so I clocked the T9900 to 2Ghz and found the minimum voltage to be .9 volts. It could easily be lower, but I can't select any lower voltages in software. I searched online for references to Q9000 undervolting, but nobody was ever able to get very far because of being limited in software and nobody I could find had attempted a hardware undervolt. A Q9000 is the same stepping at my T9900, so it should perform similarly. Based on my own and others' experiences I could find with E0/R0 stepping mobile processors, it is safe to assume that almost any E0/R0 processor will work at .9 volts at 2Ghz. I use the formula voltage^2*frequency=power/constant to give us an indication of the relative power consumption. We don't know the constant so we can't know the absolute power consumption in watts, but as anyone mathematically inclined can see, it is good for telling us how the power consumption of two processors relates to each other. A Q9000 at 2Ghz at .9 volts consumes 87.5% of the power at full load of a T9900 at 3.06Ghz at 1.1 volts. And yes, that is taking into account that the Q9000 is four cores and not two. This still doesn't even take into account the possibility of undervolting it further and/or underclocking it.
Next there is the issue of the X61 processor being BGA and the Q9000 being PGA. I used to think that this was a major obstacle. However, BGA rework is something not only possible, but common place. A hot air gun is used to heat the chip so that the underlying solder joints are melted for both removing a chip and putting a new one on. You can see videos of the process on your favorite "tube" video website. The second obstacle is how to get a PGA processor soldered onto a BGA motherboard. The answer came to be completely unexpectedly. I wanted to upgrade my T500's processor to something not only faster but more energy efficient. An E0 stepping T9900 looked like a good choice, but it cost quite a bit more than slower processors. However, I found one for sale quite cheap. It is a BGA stepping processors that had pins added to it later. After receiving it, I was curious and closely inspected the pins, comparing them to the pins on the T9400 I removed from my T500. I had a eureka moment, the pins were exactly the same! The CPU packages were identical. For the BGA processors, Intel had soldered on balls instead of pins. If pins could be soldered on, they could be soldered off. Therefore, there is nothing physically stopping a Q9000 from being soldered onto an X61 motherboard.
A lot of work was done on getting the T61 to accept a quad-core processor. It has been done and for the most part works fine. The X61 motherboard is extremely similar, and the same modifications that were done to it can be done on the X61. In addition, a hardware volt mod for the processor will be required to bring the voltage down as low as possible, in relation to everything else, that is relatively simple and is something that used to be done all the time on desktops and video cards before voltage control became something done through software. The last piece of the puzzle, however, is the BIOS. For the quad-core processor to work on the X61, the BIOS has to be modified with the extra code that was required by the T61.
I've been thinking about this for the last couple of days, and I think it would not only work, but bring a lot of benefit as well. Single-thread performance may not be very high, but overall processing power of a Q9000 at 2Ghz is 30% more than a T9900. If one would be so inclined, a Q9200 at 2.26Ghz and .9 volts has the same power consumption of a T9900 at 1.1 volts. If one would favor battery life, a Q9000 operating at the X61's default 800Mhz FSB speed would run at 1.5Ghz. At a maximum undevolt, it would likely run cooler at full load than most of the stock X61 processors. Let me know what you think about this. I can't personally do the BIOS modification, but I will look into it. If the BIOS mod can be done, then I will fully commit and buy the Q9000 and a BGA rework station. I have a "new" X61 on the way that I ordered last night, and my old X61 is dead, so I can use the motherboard to practice on.
Next there is the issue of the X61 processor being BGA and the Q9000 being PGA. I used to think that this was a major obstacle. However, BGA rework is something not only possible, but common place. A hot air gun is used to heat the chip so that the underlying solder joints are melted for both removing a chip and putting a new one on. You can see videos of the process on your favorite "tube" video website. The second obstacle is how to get a PGA processor soldered onto a BGA motherboard. The answer came to be completely unexpectedly. I wanted to upgrade my T500's processor to something not only faster but more energy efficient. An E0 stepping T9900 looked like a good choice, but it cost quite a bit more than slower processors. However, I found one for sale quite cheap. It is a BGA stepping processors that had pins added to it later. After receiving it, I was curious and closely inspected the pins, comparing them to the pins on the T9400 I removed from my T500. I had a eureka moment, the pins were exactly the same! The CPU packages were identical. For the BGA processors, Intel had soldered on balls instead of pins. If pins could be soldered on, they could be soldered off. Therefore, there is nothing physically stopping a Q9000 from being soldered onto an X61 motherboard.
A lot of work was done on getting the T61 to accept a quad-core processor. It has been done and for the most part works fine. The X61 motherboard is extremely similar, and the same modifications that were done to it can be done on the X61. In addition, a hardware volt mod for the processor will be required to bring the voltage down as low as possible, in relation to everything else, that is relatively simple and is something that used to be done all the time on desktops and video cards before voltage control became something done through software. The last piece of the puzzle, however, is the BIOS. For the quad-core processor to work on the X61, the BIOS has to be modified with the extra code that was required by the T61.
I've been thinking about this for the last couple of days, and I think it would not only work, but bring a lot of benefit as well. Single-thread performance may not be very high, but overall processing power of a Q9000 at 2Ghz is 30% more than a T9900. If one would be so inclined, a Q9200 at 2.26Ghz and .9 volts has the same power consumption of a T9900 at 1.1 volts. If one would favor battery life, a Q9000 operating at the X61's default 800Mhz FSB speed would run at 1.5Ghz. At a maximum undevolt, it would likely run cooler at full load than most of the stock X61 processors. Let me know what you think about this. I can't personally do the BIOS modification, but I will look into it. If the BIOS mod can be done, then I will fully commit and buy the Q9000 and a BGA rework station. I have a "new" X61 on the way that I ordered last night, and my old X61 is dead, so I can use the motherboard to practice on.
