I just changed my processor from an Intel E6750 to a Q6600 on an Nvidia 680i SLI board. After replacing the processor I went to the BIOS to check everything was fine and something odd happened: The CPU multiplier was listed as 8, was highlighted and had to option to change it to a value “between 6 and 9”. I of course entered 9, didn’t want to mess with the processor’s clock just yet. I saved the BIOS, restarted it, went into the BIOS again and when I tried to change the multiplier again it was fixed at 9, no option to change it this time, which is the way it's supposed to be, right?
Have someone experience that? How come the BIOS gives you the option to change the multiplier on a processor that reportedly has a locked multiplier?
Strangely enough, the processor speed was listed correctly in the BIOS at 2.4 MHz, which with a multiplier of 8 and the stock FSB of 266 MHz would have give me a speed of 2.1 MHz, not 2.4
Edit: I just changed the title to avoid confussion with the intelspeed and other power saver features. I believe my case was different.
Yes, I know, that's why I think my situation was strange, this is a plain Q6600, I shouldn't be able to adjust the multiplier. I thought at first it was intelspeed or some power saver feature in the BIOS, but those are done automatically, you cannot get in and change the multiplier under those mods
So, what you're saying is that I could have input let's say 6 and the system would have put a 9 by default and end of story? Why then allow me to even select a value?
I can confirm that you can manually set the Q6600's multiplier anywhere from 6 to 9 and it'll work. Mine's currently running with an 8 multiplier (400mhz fsb for 3.2 GHz), and speedstep drops it to 6 when idle.
OK, I'll answer my own question. Even if this guide says the multiplier on the Q6600 is "locked", is states that you cannot RAISE the multiplier over 9X, but it seems you can lower it, which prompts me to another question even if we are moving away from the subject
What would be the benefit of lowering the multiplier to 8X and raising the FSB to 400 MHz to get 3.2 GHz speed, instead of just leave the multiplier at 9X and raise the FSB to 366 MHz to obtain the same speed? I think I read somewhere that the best course of action for an overclock that takes all the potential of the CPU is to never lower the multiplier but just play with the FSB value
Again, I just want to learn as much as possible before attempting to overclok my quad
What would be the benefit of lowering the multiplier to 8X and raising the FSB to 400 MHz to get 3.2 GHz speed, instead of just leave the multiplier at 9X and raise the FSB to 366 MHz to obtain the same speed?
Because that setup also puts the front side buss at exactly 1:1 with DDR2 800 Memory. Leave the multi alone, and the 400x9 would net 3.6 GHz and a 1:1 ratio, sure! But you'd also have to be a lot more aggressive with your voltage, and therefore would also have more heat and risk. With a Q6600, it happens to work out that 8x400 requires very little in the way of extra power to run a 24x7 stable, 33% Overclock. Not a bad deal!
On another site, there's a guy who had a siggy claiming he's a founding member of the "Level~Headed Overclocker's Club". I like that idea. And I also like it when the math works out neatly.
Scotteq, thank for the explanation, it makes all sense.
My plan is to originally overclock the Q6600 to just 3.0 GHz by raising the FSB to 333 and leaving the multiplier alone at 9X. I have 4Gbs on two sticks of DDR2 800 (PC2 6400) memory, and I think I can overclock to 3.0 GHz even with stock voltages or just raising them a bit, according to what I've read. Also, I have a fairly old and moody 680i SLI board and I’m not sure how it’s going to take it, every processor is different and with my board it can complicate matters
Should I attempt to go over the 3.0 GHz I’ll keep your advice in mind
The 680i SLI may be an older board, but I have had very good luck with it. I have overclocked 2 processors on this board. I have my e6600 oc'd to 3.3ghz with fsb of 1650 and a x8 multi and my cousin's Q6600 to 3.6ghz.
Get the latest bios and your shouldnt have any issues getting over 3ghz.