Extreme Bus speed fluctuation

[theDTP]

Installed a 4790k today to replace my 4670k and my bus speed is all over the place, all the way from 5MHz to 200MHz.

It's been really hard to grab a validation through CPU-Z but I managed to grab one the shows it.

https://valid.x86.fr/e8m67w

I've got it working now, the i7 clocks the same as the i5 but as soon as I change my Bus Speed to 100 or 100.1 (because at 100 it sits at 99.76) then it starts happening, I have to leave the Bus Speed on Auto to stop it from happening.

Any idea why?

At one point my i7 was sat at 10.5GHz

 

[theDTP]

I know the screenshot and the information don't match but the screenshot is messed up, in person it was actually changing.

 

[theDTP]

Right, never mind I fixed that.

But now I can't get in to my bios, Windows boots as normal but when I try and press the Delete key to enter bios I just get a black screen, any ideas?

 

[theDTP]

Never mind that also haha.

 

[AlienALX]

Right, never mind I fixed that.

But now I can't get in to my bios, Windows boots as normal but when I try and press the Delete key to enter bios I just get a black screen, any ideas?

I had this on my X79 Gigabyte. Try updating the bios.

 

[theDTP]

I had this on my X79 Gigabyte. Try updating the bios.

I'm on the latest bios, cleared CMOS which fixed it, I was scared to clear the CMOS and then not be able to get back in but I gave up.

Still not managed to fix the bus speed situation, has to be on 99.76, anything higher causes the bus speed to change continuously.

I'm happy with it now, stable at 4.8GHz. Well, 4.78 due to the bus problem but it will do, I can actually game now, my i5 4670k was sat at 100% usage constantly in BF4.

 

[AlienALX]

That is what mine used to do. If I cleared CMOS and removed the battery it would let me in once, then start the black screen nonsense. As I say though, I resolved that with a bios update.

 

[theDTP]

That is what mine used to do. If I cleared CMOS and removed the battery it would let me in once, then start the black screen nonsense. As I say though, I resolved that with a bios update.

Ah, cheers for the replies, if it does it again I'll flash the second most recent bios

 

[AlienALX]

Ah, cheers for the replies, if it does it again I'll flash the second most recent bios

If the board has a dual bios switch try that. My second bios was much better behaved than the first, oddly

 

[Wraith]

My 4790K is set to auto too and it fluctuates between 99.9 - 101.1 never noticed this before...

 

[theDTP]

My 4790K is set to auto too and it fluctuates between 99.9 - 101.1 never noticed this before...

Yeah that's normal apparently, not bloody 175MHz though :mellow:

Sorted now, have to leave it on auto, if I set it above 99.76, sh*t starts going horribly wrong.

Probably the beta bios I'm using.