Thinkpads Forum

I'm thinking of doing the BSEL mod on my t61 to replace my T9300 with a P9700, what RAM should I buy? I only plan on having 4gb in total, I don't think I will need 8gb.

I'm thinking of trying exactly the same thing on an older Intel video
mother board that I have. So, I'm interested to hear the answer.
I'm looking for clear instructions on:
1. How to do the BSEL mod on an Intel video motherboard
2. How to modify the RAM

As I understand it, the BSEL mod sets the clock gen for an FSB of
1066, the chip set does not know this and uses the RAM timing for 800
FSB so you have to copy the RAM timing info from the 1066 slot to the
800 slot so that the chip set uses the correct timing. Exact instructions
for this would be helpful.

I seem to be getting a lot of Kingston RAM these days, can it be modified?

Wondering, if the BSEL is done will all the Penryn dual cores work with
Middleton BIOS, P9700 on up to X9100?

I have to guess that the 45nm process got better an better so these
should run cooler.

You need to get SODIMMs which have an SPD chip that is unlocked so that the timings can be modified. From what I understand the majority (80%) are locked down.

Since I myself am also interested in this (so that I can put a CPU in with a TDP of 25 watts) I'm wondering if the SPD chip can just be desoldered and replaced with one that A) already has the 1066 timings--maybe could be taken from a DDR3 SODIMM, or B) is already unlocked.

Pin mod shown here, looks too risky for me unless 30ga wirewrap wire works
also tells how to solder to PLL:
http://forum.thinkpads.com/viewtopic.ph ... 20#p718771

I'd probably go for the PLL mod.

Another good post here:
http://forum.thinkpads.com/viewtopic.ph ... 30#p728624

j.harris wrote:I'm thinking of doing the BSEL mod on my t61 to replace my T9300 with a P9700, what RAM should I buy? I only plan on having 4gb in total, I don't think I will need 8gb.

Is your motherboard Intel or Nvidia?
I actually remember reading that the Intel video version has issues since the
overclock also increases the video subsystem's speed if you don't alter the
multipliers. Don't remember how they got around this issue.

Mine is nvidia, actually one of the failure prone older ones, I have it undervolted to .95v via the custom BIOS.

Pete B wrote:

j.harris wrote:I'm thinking of doing the BSEL mod on my t61 to replace my T9300 with a P9700, what RAM should I buy? I only plan on having 4gb in total, I don't think I will need 8gb.

Is your motherboard Intel or Nvidia?
I actually remember reading that the Intel video version has issues since the
overclock also increases the video subsystem's speed if you don't alter the
multipliers. Don't remember how they got around this issue.

I have to research this since the X61 family use the same chipset with Intel video
and the BSEL mod is working fine here:
http://forum.thinkpads.com/viewtopic.php?f=30&t=115785

Looks like you need a special BIOS for the P processors:
http://forum.thinkpads.com/viewtopic.ph ... t=BSEL+mod

Is it a microcode issue?

In German:
https://thinkpad-forum.de/threads/13201 ... et-und-T61

I think that I finally understand this a bit better and will keep my notes here
if people don't mind. I think that this applies to both the X61 and T61 families.

The BSEL lines have resistors between the processor/chipset side and the PLL.
The simplest case is to hard wire the PLL side to 1066 and use a correct 800
FSB CPU in the socket. This has the CPU and chipset "think" that they are
running at 800 FSB but the PLL side mod is actually forcing it to 1066. Both
the CPU and Chipset/RAM are overclocked in this situation. People say that
the T8300 runs well in this situation for example where the actual clock is then:
2.4G *1066/800 = 3.2 GHz
No BIOS mod is required since these are compatible processors and it sees the
correct speed on the CPU/chipset side.
The RAM also runs overclocked and this is the point of this thread, the chipset
reads out the 800 timing when it should be reading the 1066 timing and the
mod discussed here is to copy the 1066 timings to the 800 location in the SPD,
thus keeping the RAM at stock approved timings.

There are two complications when installing a 1066 FSB processor, it tells the chipset
to run at 1066 which it was never intended to do. The system will not boot with
the BSEL lines indicating anything over 800 since it is an unapproved processor and
speed for the chipset.
The BSEL lines on the CPU side must be forced to 800 to make the chipset/BIOS
"happy". Now the PLL sees 800 so the above PLL mod must also be done to take
it back to 1066. Finally, the BIOS microcode was never included for the later
1066 processors so a BIOS update is required for it to boot. Once these conditions
are met it is the same as above and the RAM timings must also be copied in this
situation. I'd rather do the CPU side BSEL mod at the resistor on the MB rather
than hack up the socket, not sure if this is an option.
An interesting thing about this is that only the chipset is overclocked and not the CPU
or RAM.

Does the Middleton BIOS accommodate 1066 FSBs? I don't recall.

Nope.