Thinkpads Forum

This is very old story can be found on pages of NBR forum or here.
Main concept SU9400 and SU9600 working on 800MHz FSB (and memory also works @ 800MHz out of 1066;). With BSEL mod (pinmod is not accurate term because SU9400 and SU9600 haven't pins they are soldered to mainboard) FSB can be tuned to 1066. And it gives 1.8GHz for SU9400 and 2.13 for SU9600.

Some weeks ago i have built my X301 with SU9600 from two X301. And mainboard with SU9400 become spare. And i become ready to make some fun. Couple of days ago i have made BSEL mod like described there - GoogleTranslated. And it give 1.8GHz... and give some unstability. Memtest x86 found errors on healthy sticks (it have passed all tests on unmodified X301). And Win7 going to BSOD on heavy load (eg on getting WEI). This means that voltmod is also needed. BUT voltmod for what? CPU or northbrige (memory controller)?
Or may be SU9400 is not good CPU for BSEL mod? Or may be i have forgot something while modding X301?

Check the memory timings. The memory might be using its SPD timings for 800Mhz instead of 1066Mhz, which could lead to instability. If the timings are incorrect, flash the SPD so that the 800Mhz timings equal the 1066Mhz timings. Alternatively, a memory volt-mod would probably suffice. Are the memory modules DDR3 or DDR3L?

My X301 runs 100% stable at 2,13GHz. I use 1333MHz RAM. You can't use 1066MHz RAM. (aka the standard RAM it was shipped with)

Qing Dao wrote:Check the memory timings. The memory might be using its SPD timings for 800Mhz instead of 1066Mhz, which could lead to instability.

You've got point. Definitely - In normal X301 - it use 800MHz timings 6-6-6-15 (from Memtest x86). The same modules (samsung 1066 - FRU 43R1969) in modded X301 runs @ 1066 with 6-6-6-15 timings (from 800)! Why memory controller have mistaken???
I have checked other Thinkpads working @ 1066 (X200, T500 and T410) all have 7-7-7-20 on different memory modules.

Qing Dao wrote:If the timings are incorrect, flash the SPD so that the 800Mhz timings equal the 1066Mhz timings.

How can i do this? I have seen SPD mod procedure for 1066 FSB T61 frankenpad but there are flash image have been already prepared for this mode. If you can post link about SPD modding it will be sufficient. But now i'll go and ask google;)
And yes it is normal DDR3 (not Low voltage) modules.

BTW - i can search shelves for 1333 DDR3 modules and try them.

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Addendum.

Memory controller (north bridge) have mistaken because we have cut line BSEL1 from CPU to clock generator, but there is other path from CPU to north bridge. And it still indicate that CPU is 800MHz so memory controller takes 800MHz profile from memory SPD.

I have found 2 pairs of DDR3 memory sticks which have double passed memtest86 on out of spec timings (6-6-6-15 @ 1066).
- Kingston KVR1066D3S7 (designed for 1066) with Elpida chips
- AMD R334G1339S1S-UO (designed for 1333) (with AMD chips

Conclusions:
This mod not only increase CPU, memory and bus (FSB) speed but makes memory work at low latency. Some memory sticks can't work in this regime but some can.

PS
600X and Qing Dao can you check what timings (and what memory) working in your X301.

PPS
Now i have prepared to make final mod on main (1.6GHz) X301.

Do you have a better photos ? Thx