790i ultra sli overclocking question

[borisof007]

Hello!

I'm normally patrolling the video card forums, but I did have a quick question about my setup.

I'm running the following:

Nvidia NForce 790i Ultra SLi
Q9450 (currently oc'd to 3.2ghz)
4 gb DDR3 1600 OCZ Platinum

Now when I went to set my memory's speed to 1600, my FSB clocked my processor to 3.2ghz as it "linked" the two of them. Not 100% sure on exactly what it means, other than the speed on one directly impacts the other.

What I want to know is if with my motherboard I can overclock my CPU more and keep my memory speed the same? I have a plentiful PSU (PC Power and Cooling 750 watt Silencer) and am only running 1 video card (GTX 285), 3 hdds (1 100gb SSD, 1 750gb and 1 tb magnetic hdds), and a DVD-RW drive.

I have a Zalman 9500 CPU heatsink/fan combo, seems to keep it very cool. When fully stressed I can touch the fins and they're cold. ( http://www.advanced2000.com/mmTEST_SHOP/Images/Zalman%20CNPS%209500.jpg ).

Also, if I CAN overclock it more without linking my memory to it, what's the maximum you think I can take it? I'm thinking 3.6 ghz on air before problems, but I'm not too sure.

 

[Nils]

Hi,

I had a Nvidia 680i motherboard in the past and it also had the option of linking the mem to the fsb. However in my case I could simply set it to unlinked and then enter any ram speed I wanted and the mobo would set the ram to the closest possible speed. Maybe yours has the same option.
Otherwise, you should be able to choose from a set of fsb:ram ratios. Maybe you can use these to keep the mem speed down when upping the fsb.

Hope it helps

 

[ace700]

yes you can there should be an option where you change your fbs speed to either link it, 2:1, 1:1 or unlinked

 

[ko888]

"Linked" means that the CPU Frequency (MHz) changes proportionally as you change the FSB speed.

From the main CMOS Setup Utility menu navigate as follows:

Advanced Chipset Features > FSB & Memory Config > FSB - Memory Clock Mode

Change the FSB - Memory Clock Mode to [Unlinked]

You should now be able to set the FSB (QDR), MHz and the MEM (DDR), MHz separately.

 

[borisof007]

Ok, so I'll unlink the two of them, and does increasing the FSB speed increase my CPU clock speed? Sorry if that sounds like a stupid question.

Also, at what point will I know if I'm being underpowered as far as voltage is concerned in overclocking my CPU? I doubt I'll go that high, but I'm just curious.

 

[ko888]

Ok, so I'll unlink the two of them, and does increasing the FSB speed increase my CPU clock speed? Sorry if that sounds like a stupid question.

Also, at what point will I know if I'm being underpowered as far as voltage is concerned in overclocking my CPU? I doubt I'll go that high, but I'm just curious.

Changing the FSB speed will still change the CPU's clock speed.

Have you been running any testing applcation(s) to determine if your overclock is stable? I've used Prime95 and IntelBurnTest for testing the stability of my overclocks.

If you get an error when you run the stability testing application you raise your core voltage by the next increment allowed in the CMOS Setup Utility and rerun the stability testing application. I use CPU-Z to determine that I haven't raised my Core Voltage beyond Intel's voltage specs for my CPU model to achieve that stability. Keep incrementing the core voltage and rerunning the stabilty test application(s) until you reach stability without going over Intel's voltage specification for your CPU model.

 

[Nils]

Ok, so I'll unlink the two of them, and does increasing the FSB speed increase my CPU clock speed? Sorry if that sounds like a stupid question.

Also, at what point will I know if I'm being underpowered as far as voltage is concerned in overclocking my CPU? I doubt I'll go that high, but I'm just curious.

Basically the cpu clock speed is determined by multiplying the cpu multiplier by the fsb speed. So you can OC the cpu by only raising the fsb, by only raising the cpu multiplier or by changing both. If you would suddenly hit a "wall" in oc'ing, meaning you can't get the cpu clock any higher, changing oc method might help.

 

[borisof007]

Best answer selected by borisof007.