P55A-UD4 20x/21x multiplier BIOS dependant

[early]

I'm using this motherboard with an i5 750.

It seems like with the BIOS version F14 I can have 20x multi, but I can't have the 21x one. (When I try it just goes back to 20x by itself.)

However, with F15 I can have 21x, but not 20x.

Is this normal or does it just happen to me? I have the rev. 1, BTW.

[Acebmxer]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

How did you flash the bios? Q-flash or with @bios. When you flashed did you keep "dmi pool data"? Did you load "Optimized Defaults" after flashing?

[wazza300]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

I think some bios's let you set 21x and some 20x taking into account that Intel turbo boost adds the extra 1x to the 20x if its enabled,it makes no difference to the 21x if Intel turbo boost is enabled or not,hope that made sense

[early]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

How did you flash the bios? Q-flash or with @bios. When you flashed did you keep "dmi pool data"? Did you load "Optimized Defaults" after flashing?

I used @bios. (Qflash didn't work for me last time I tried.)
I did check to load the defaults, but I left the DMI thing unchecked. What does that thing do?

I think some bios's let you set 21x and some 20x taking into account that Intel turbo boost adds the extra 1x to the 20x if its enabled,it makes no difference to the 21x if Intel turbo boost is enabled or not,hope that made sense

I see. Kinda weird if it's so random.
BTW, the BIOS settings were exactly the same on both F14 and F15 when I was trying all this (tried with different CPU frequencies, even auto).

[wazza300]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

I would reflash but untick keep dmi pool data,then load optimized defaults,dmi pool data checks all your components before passing it on to the os I think,just make sure Intel turbo boost is enabled and use the 21x multi

[Lsdmeasap]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

Wazza is right, some BIOS let you manually set max multi (With Turbo disabled) and some do not. So some BIOS you would be able to set 21 manually and others you'd need to set 20 and enable turbo to get 21, not sure why they do that but I have seen it in a few BIOSes

[early]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

Since I don't like to leave mysteries behind.. it was indeed because of the Turbo thing being enabled in F15. I guess I overlooked that setting.
So with Turbo on I get x21 max and with it off I get x20 max.

That being said: is Turbo simply another way of saying x21 multi? Can it be then used for higher overclocking etc.? Does it affect all 4 cores?

It doesn't seem to affect the voltage I set manually, which is good. EIST also still works. So it looks good so far. But please let me know if there's anything I should know about it.

[Acebmxer]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

Since I don't like to leave mysteries behind.. it was indeed because of the Turbo thing being enabled in F15. I guess I overlooked that setting.
So with Turbo on I get x21 max and with it off I get x20 max.

That being said: is Turbo simply another way of saying x21 multi? Can it be then used for higher overclocking etc.? Does it affect all 4 cores?

It doesn't seem to affect the voltage I set manually, which is good. EIST also still works. So it looks good so far. But please let me know if there's anything I should know about it.

Short answer is "YES".

Some boards let you cpu multi manually above stock with turbo disabled some boards you need to enable turbo to select a higher multi.

Yes you can overclock further because your cpu multi is now higher. 20x 200 (bclk)= 4.0 Ghz. but 21x200 = 4.2 Ghz.

You may be able to run 21x multi at stock speeds with out having to increase voltage but as you overclock you may find that 20x200 take less voltage then 21x190 for the same ghz speed.

[early]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

I checked with CPU-Z and it says all 4 cores work at the same speed (I was asking about this because I read somewhere that Turbo Boost only affects 2 cores..).

You may be able to run 21x multi at stock speeds with out having to increase voltage but as you overclock you may find that 20x200 take less voltage then 21x190 for the same ghz speed.

Really? I've always thought the opposite is the case, that a higher multi is always best. Is this a new thing with the i5/i7 CPUs?
(I've actually skipped a few generations of CPUs, last time I did serious OCing was with a 939 AMD, to give you an idea.. well, some Core 2 Intels, too.)

[Lsdmeasap]

Re: P55A-UD4 20x/21x multiplier BIOS dependant

What he meant by that is many CPU's require much more voltage to stabilize when using a even CPU multiplier, not all though but enough for everyone to know about it.

So it would be worth trying an odd multiplier to see if you can run the same speeds with less voltage