Understanding Unlocked Multipliers......

[Cybrnook2002]

I am soon going to get one of the QX6850's from the retailedge. I am going ot be swapping from my E4400 @ 3.0 GHZ to the QX6850 @ stock 3.0 Ghz. My E4400 has a locked multiplier of 10. So im using 10 x 300FSB for a total of 3.0 GHZ. And if I understand correctly, thats a %50 OC putting my stock FSB from 800 CPU to 1200. Ok, the 6850 is 1333 FSB CPU with an unlocked multiplier. Does this mean I can change just the multiplier to achieve a nice oc? By changing the Multiplier, how is this effecting FSB? What else is happening by changing Multiplier? Do I have a limit on how high or low I can set my multiplier? Also, im on a P965 chipset. So, I have a limit of native ram support up to DDR2 800. However, I have OC'd my ram close to 1000. So thats fine, also by default with my new bios flash, my P965 supports the 1333FSB 6850 no problem. But, as this is going to be my first unlocked multiplier. Does anybody have any good advice.

[kenkickr]

Isn't the "unlocked" multi on those for only going down? Intel's use that thing could SpeedStep, the equivalent to AMD's Cool 'n Quiet which will drop the multi to slow the cpu down when your not doing much and then ramps the speed backup when needed just so your not wasting energy. So now you could achieve a higher FSB/DRAM speed?

[Cybrnook2002]

Well, No.It has C1E and speedstep. But that has nothing to do with the unlocked multiplier. My E4400 also has speedstep and C1E which drops the multiplier if enabled from 10 to 8 then to 6. But with the QX, its REALLY unlocked, so in the bios for example with my E4400. Instead of 10 x 300 for 3.0 GHZ, I could do 12 x 300 for 3.6 GHZ. But, my question is what else is happening when I do that. Is it changing my CPU / RAM ratio? My DDR speed? What else is happenng? Is it jsut making my CPU and RAM divided easier to work with, so as I increase the PCU spd with the multiplier, it does not have such a drastic raise in RAM speed?

[Tatty_One]

Phew, lots of questions there, to kind of address them all in one swoop, I think on the QX6850 the unlocked multi range is 6-12, the chip defaults at 333fsb (quad pumped) x 9 on the multiplier.

Of course if you simply raise the multi to 10x yes of course the speed will then naturally rise to 3.33gig, of course adjusting VCore/FSB and NB/SB volts accordingly.

You will have to play with the right multi/FSB combinations to get the max performance out of your chip, at the same time as balancing your memory speed with the FSB and available memory dividers, this can be quite time consuming, for example, you may find that to obtain the speed of 3.66gig, simply raising the multi to 11 will give you that speed but it may need less volts if you go 10 x 366 FSB.....does that make sense, and when you get to MAX overclocks, more often than not you will find a multi combination that gives you speeds that other multi/FSB combo's cant acheive, it's that balancing act with stability and volts/heat......always take into account memory speed/performance, quite often 50mhz on the CPU will make your system slower if to acheive that you have to drop a memory divider so your memory is under performing to it's capabilities...............make sense?

[Cybrnook2002]

Yes, THANK you soo much. So its seems that unlocked multiplier is jsut going to be giving me a larger scope to work with to find my sweet spot. For example with my E4400. the multiplier is locked. But, I have done two overclocks that I liked. First, I had set DDR spd to 800. Then the Divider at 533 I think. Im not sure, my bios gives me a display telling me what everything will be running at when i change something. Anyways. I got 2.7 GHZ on the cpu and DDR 933 speed. That was a nice oc on the CPU and a hella oc on the ram. However, I found that by adjusting the dividers again, I was able to raise the CPU to 3.0 while retaining the RAM at 800. With this oc I got the best peformance. So, It seems with the 6850, I will have a much easier time finding a sweet spot for both.( naturally adjusting voltages as needed and watching for heat) But, do you think its safe to say that even though my board does not support it natively, can I run DDR 1066? Seeing as how I can OC up to these speeds, could I by default boot into 1066 RAM by having the SPD set to 800 and have a stable OC on the processor while ram is running at 1066.

[Tatty_One]

Originally Posted by Cybrnook2002

Yes, THANK you soo much. So its seems that unlocked multiplier is jsut going to be giving me a larger scope to work with to find my sweet spot. For example with my E4400. the multiplier is locked. But, I have done two overclocks that I liked. First, I had set DDR spd to 800. Then the Divider at 533 I think. Im not sure, my bios gives me a display telling me what everything will be running at when i change something. Anyways. I got 2.7 GHZ on the cpu and DDR 933 speed. That was a nice oc on the CPU and a hella oc on the ram. However, I found that by adjusting the multipliers again, I was able to raise the CPU to 3.0 while retaining the RAM at 800. With this oc I got the best peformance. So, It seems with the 6850, I will have a much easier time finding a sweet spot for both.( naturally adjusting voltages as needed and watching for heat) But, do you think its safe to say that even though my board does not support it natively, can I run DDR 1066? Seeing as how I can OC up to these speeds, could I by default boot into 1066 and OC from there?

2 things, firstly your E4300 was locked upwards but should not have been downwards locked......an overclocker (although of course I am retired )should always try to obtain the speed going down on the multi and up on the FSB as sometimes that does give a better memory balance but also in some cases, it may be acheivable on less volts, I have had a number of CPU's where for example 3gig at 10 x 300 required more volts than 3gig at 9 x 333 if that make sense, hence me mentioning the need to play around to get the best balance, remembering that also most CPU's and mobo's (well actually the NB) can have FSB walls at certain speeds.

Yes your memory should be OK at 1066mhz, you can only try, just make sure you loosten the timings and give them slightly more voltage to compensate, you can always try to lower and tighten once you get there, again......some juggling required.

[JBravo]

@ Tatty one

Thanks for the info you have supplied. It gave me a new idea to go and play with

Also, I would like to ask, I've got an old mobo that does not allow me to adjust voltages in the bios. However, i have been able to OC from 3.2ghz to 3.44ghz on standard voltages ( orthos stable for 2 hours ). Temps at this speed is still low @ 40C idle and 58 load.

My multiplier is set to 16x 215 = 3440 but can be dropped to 14x fsb

Now, I've been able to post and boot into windows up to 3.68ghz, but it becomes unstable under load very quickly. I checked the voltages using cpu-z and i can see it dropping under load. I am wondering if my mobo isn't dropping the cpu voltage to try and reduce the temps as i can see i dropping as the temps rise.

now i want to try reducing the multiplier and upping the fsb to get the same 3.44ghz and check the vlotages at max load.

Do you see any possible problems with my ideas?

thank you for any help in advance

[eazy1968]

It is also dependable of what type of motherbord you use !!

[JBravo]

its shown in my system specs

GA-8S661FXMP-RZ

[hat]

the only thing that happens when you change the multiplier is the cpu runs at a different speed.
Ex you are getting a QX6850 that has 333x9 which gives you 2997MHz (pretty much 3 gig). If you changed it to 10, you would be at 333x10 or 3.33Ghz. That's all. Memory stays the same.

IIRC there's a limit of 25, but who in the hell would use a multi like that anyway?

[Tatty_One]

Originally Posted by JBravo

@ Tatty one

Thanks for the info you have supplied. It gave me a new idea to go and play with

Also, I would like to ask, I've got an old mobo that does not allow me to adjust voltages in the bios. However, i have been able to OC from 3.2ghz to 3.44ghz on standard voltages ( orthos stable for 2 hours ). Temps at this speed is still low @ 40C idle and 58 load.

My multiplier is set to 16x 215 = 3440 but can be dropped to 14x fsb

Now, I've been able to post and boot into windows up to 3.68ghz, but it becomes unstable under load very quickly. I checked the voltages using cpu-z and i can see it dropping under load. I am wondering if my mobo isn't dropping the cpu voltage to try and reduce the temps as i can see i dropping as the temps rise.

now i want to try reducing the multiplier and upping the fsb to get the same 3.44ghz and check the vlotages at max load.

Do you see any possible problems with my ideas?

thank you for any help in advance

No problems with that although, it's not the temps that are causing your voltage to reduce under load/overclock, it's VDroop and all motherboards suffer from it to a certain extent, can you change voltages on NB/SB and FSB?

[JBravo]

Originally Posted by Tatty_One

No problems with that although, it's not the temps that are causing your voltage to reduce under load/overclock, it's VDroop and all motherboards suffer from it to a certain extent, can you change voltages on NB/SB and FSB?

No I can't adjust ANY voltages...My cpu is currently only 7% overclocked, so I'm thinking it should still go up to at least 20%.

Do you possibly know of any software that might allow me to adjust voltages from windows?

Its funny how the volts drop, it starts off at 1.242 idle an while running orthos, it steadily dropped to 1.184 and would probably go lower ( this was after only 20mins )

Any ideas?

Thank you for helping