Not sure if it's suitable to post this here but apparently notebook review is not showing up properly on my laptop
Anyway, I hope that I'm the first one here to finish this task
Special thanks to Leokim for those two threads that confirmed the possibility of installing a 1066MHz CPU onto 965 chipset
http://forum.51nb.com/thread-1310165-1-1.html
http://forum.51nb.com/thread-1287155-1-1.html
And xiaofei290 for the modified BIOS
http://forum.51nb.com/thread-1062553-1-1.html
After 2 days of work, I figured out how this works. It's a quite complicated task which involves not only BIOS modification, But also modification to PLL, CPU socket, RAM timing and a bit of soldering. Don't be scared
It's not that complicated, for method please see el-sahef's methos on page 2
Special thanks to el-sahef for the quad core mod and highsun for the improved BIOS
el-sahef's Quad Core method: http://forum.thinkpads.com/viewtopic.ph ... 30#p728624
https://fbcdn-sphotos-c-a.akamaihd.net/ ... 2381_o.jpg
It might be pointless to do so, especially in the year 2013, which even X9100@3.7Ghz couldn't hold itself against the new i7-3520m, and the graphics card is even more bottlenecking ><, even with 2503 ultrabase and HD7750.
But I can't cope with 16:9 at all..... And T61 is probably the best machine for me..... :/
really love it's SXGA+ screen.... Just hope it could last slightly... longer...
Notice: The following CPUs will NOT post with the xiaofei290's BIOS:
(Tested)T7300, T7500, T7700, (persumably) T7250, T7800, X7800 and X7900
The following CPUs will work without any modifications
(Tested)T7100, T8100, T9300, T6670 (persumably) T6570, T6900, T8300, T9300, T9500 and X9000
The following CPU will work after BSEL modifications:
(Tested)T9550, T9600, X9100, T9900, P8800(SLGLA), E8335 (persumably) all other 1066Mhz FSB Dual Core C2Ds
The following CPU works with further modification:
(Tested)Q9000 (credit to el-sahef)QX9300 (credit to joker4791),Q9100, (persumably) QX9200(ES)
Recommended CPUs (considering performance, heat and cost):
E8335, T9800, T9600, P9600, P8800, P8700
Further notice: 1.Unless you have a X9100 or QX9300, avoid Elpida/Hynix/Crucial 4GB DDR2 as they have SPD locked
2. If you have a T61p with FX570m and you wanna flash the highsun's Nvidia undervolt BIOS, I'd recommend 1.00V at least
3. C0 stepping Q9100 ES (QDRS) does not work on any of the BIOSes, and persumably all C0 stepping Quad Core Engineering samples will not work either
4. If you are upgrading to T9800 or above, I'd recommend 90W psu for T61 with intel graphics, and preferably a 135W for nvidia graphics. (to be confirmed later)
Known problems of Quad-Core mods, apart from overheating:
1. Two cores operates normally, while the other two cores are always running at lowest clock speed(1.6 Ghz)
Temporary Solution: a. Use throttlestop or CPUgeine to adjust the multiplier
b. Just ignore it for the sake of cooling

2. Insufficient total power supply/CPU power supply
When running intensive tasks such as Intel burn test on Quad-Cores, the laptop might suddenly restart/shutdown. Problem more severe on the nvidia graphics machines. elsahef and amwrdfe(51nb) suggested that the CPU current limit is responsible for this. But my testing suggested that the total power limit plays the role. For details please check next few pages
Temporary Solution: use throttlestop or CPU geine to undervolt the CPU, almost all C2Qs are capable of running full speed at lowest voltage(1.05V)
3. Occasional boot failure.
qwerty Andreas and me have both encountered this problem. However I'm not really sure if his problem is really exactly the same type as mine.
Symptoms: sometimes completely black screen, sometimes the thinkpad logo screen shows, one can enter the BIOS but the laptop fails to boot.
Reason: unknown, might be APIC/ACPI/CPU multipliers
Solution: put a 1066mhz FSB Dual core CPUs in, start the laptop and enter the desktop, then shutdown and put the Quad-Cores back in, everything should be okay.
4. Device manager only shows two CPU cores, under both Windows 7 and XP.
Doesn't really matter ╮(╯▽╰)╭
5. If the CPU throttles due to overheating, it will stick at the lowest multiplier until the next restart
Solution: throttlestop or watch the temperature
6. adjusting clock modulation in throttlestop gives a BSOD
Reason: unknown
Solution: N/A, don't touch it
7. disabling "CPU multi-processing" in BIOS will only disable one CPU core and 3 cores still runs
Reason:(guess) Some part of the BIOS are not notified of the additional cores, or some control circuit still needed.
Solution: What? you've done all the work to have a Quad Core running as a single core??!!
