BSEL pin questions

Looked at some Intel docs for PD and CD/CS, they both have 3 BSEL pins.
Is it possible that more than the defined BSEL combinations work for CD, like 200 and 266 MHz?
After all, this is the specs for the CPU's, but it's up to the chipset if it's supported. Would be great for laptops, just like going 100 to 133 MHz with a PM, although that was already defined.

Code:

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BSEL2  BSEL1  BSEL0  PD  P4HT CD
  L      L      L    266 r    r
  L      L      H    r  133  133
  L      H      H    r  r    166
  L      H      L    200 200  r
  H      H      L    r  r    r
  H      H      H    r  r    r
  H      L      H    r  r    r
  H      L      L    r  r    r

r=reserved

---

Looks interesting. :)

Maybe LHL oder LLL is possible at the AOpen i975Xa-YDG, because the i975X has to now about this setting.

The AOpen board has two jumper to select the FSB Range in the BIOS:
http://www.oc.com.tw/article/0601/im...-060124-07.jpg
I think its possible that the jumper do nothing else than to switch between the BSEL pins. :rolleyes:

cu, BitpowerPM

That Aopen mobo must be able to handle 266 MHz since it's a desktop chip. A wire mod will bump up your 1.66 GHz to 2.66 GHz, a nice start with a 60 % overclock. Then you start overclocking in BIOS....

I wonder about these reserved BSEL combinations, can you go from 133 to 200 MHz in a PM laptop? Or is that BSEL combination blocked in the chipset? If not then people wouldn't have to downgrade to a 100 MHz 7x5 CPU just to be able to overclock.

The old Pentium M and Pentium 4 S478 uses only two BSEL pins, for some reason a bit different from each other (marked in red):

Code:

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    Pentium 4                    Pentium M
BSEL1  BSEL0  FSB            BSEL1  BSEL0  FSB
  L      L    100              L      H    100
  L      H    133              L      L    133
  H      L    200              H      L    r
  H      H    r                H      H    r

---

What happens if you isolate the BSEL1 pin on CT-479 systems? Will you get 200 MHz FSB? Break the pin off is one way, but maybe not the best, some people used to do that on old P4M CPU's to make them run at 200 MHz. Maybe it could solve PAT issues, or make the P4P800-VM overclock better (Isn't there some kind of problem with overclocking the P4GD1 too? With the PCIe... don't remember). Have anybody tried?

Mats: I only see BSEL0 and BSEL1 on the CS/CD package pinout.

Quote:

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Originally Posted by Warship

Mats: I only see BSEL0 and BSEL1 on the CS/CD package pinout.

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Look again here. Page 46, BSEL2 is pin C21. Also listed in the table on page 47.

Ah, now I see it. So we only need to u-wire BSEL0 and BSEL1 to VSS, and she should boot at 266xN?

Quote:

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Originally Posted by Warship

Ah, now I see it. So we only need to u-wire BSEL0 and BSEL1 to VSS, and she should boot at 266xN?

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AFAIK. But since I haven't tried I'm not sure of anything.

it's a shame this wont work on the i945gm chipset, according to the datasheets, it wont work with reserved bsel settigs, only 133 and 166 are defined.

the reserved settings might work on the i975 boards though. try it!

Quote:

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Originally Posted by cirthix

it's a shame this wont work on the i945gm chipset, according to the datasheets, it wont work with reserved bsel settigs, only 133 and 166 are defined.

the reserved settings might work on the i975 boards though. try it!

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I'm not sure what to think. The FSB limitations are determined by the chipset, primarily. Well yeah, a CPU may have a FSB limit as well, but that's not the issue here since all Intel CPU's today can handle 266 MHz AFAIK.

Maybe I didn't look at the right place, but I didn't see any FSB speeds at all for the 975X in it's datasheet. Intel tell us about the FSB in the CPU datasheets instead. So if a chipset is capable of 200 MHz they won't tell us as long as there are no CPU's available with that speed (read Merom).

So as I said in the Yonah thread, it's worth trying 200 MHz in 945 laptops too, you never know! I think it's more likely than getting 266 MHz.

Quote:

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Originally Posted by Mats

I'm not sure what to think. The FSB limitations are determined by the chipset, primarily. Well yeah, a CPU may have a FSB limit as well, but that's not the issue here since all Intel CPU's today can handle 266 MHz AFAIK.

Maybe I didn't look at the right place, but I didn't see any FSB speeds at all for the 975X in it's datasheet. Intel tell us about the FSB in the CPU datasheets instead. So if a chipset is capable of 200 MHz they won't tell us as long as there are no CPU's available with that speed (read Merom).

So as I said in the Yonah thread, it's worth trying 200 MHz in 945 laptops too, you never know! I think it's more likely than getting 266 MHz.

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certainly worth trying, but it probably wont work

Any news?

Jes..So what about the Mods, are there any detailed constructions, for Pinmodding Yonahs in Notebooks?

Thanks

bump.

Anyone have info about trying this on Meroms? I've got a T5500 and a T7400 at 667fsb. Would be nice to try pushing them a bit quicker.. :D

STevil, is that with a desktop or a notebook? I wish I had my own merom notebook to do testing on, but results from people so far have shown that users with 533 meroms (maybe yonah) when manipulating bsel to 667 results in proper 667fsb, however cpu gets stuck in lowest multiplier.

As for upping above 667 on your chip, the bios has to have support for being able to read the proper bsel flags. Hence why like in the older days, when you threw a 133fsb chip in a board that only supported 100, you're still stuck with 100. However, in some boards, it may not even post at all

Both my chips are 667 at default. 800 (200mhz FSB) is the next step.

Notebook. Need to work on a better cooling setup before testing happens.

bump?

sorry stevil. most all notebooks don't have the bios programming to understand 200fsb. you could manipulate bsel but it'll either still boot at a lower setting or not post at all.