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Newbie overclocking voltage question

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July 1, 2008 10:09:42 PM

Hi. I am buying a new computer tomorrow with a Q9450 and an Asus Rampage motherboard. I am hoping to overclock it to around 3.2 to 3.6ghz, and it will be my first time overclocking a computer.

I read the guide here about overclocking quad cores and I have a basic understanding about voltages, but there are some things I don't understand. From the guide, I got that voltages can be classified as...

1) CPU Voltage
2) Northbridge Voltage
3) Southbridge Voltage
4) RAM Voltage
5) FSB Termination voltage

I downloaded the asus rampage motherboard manual and found all these voltage settings, but the motherboard also has...

A) CPU PLL Voltage
B) SB 1.5V Voltage

Does anyone know what CPU PLL and SB 1.5v Voltage are? Should I leave these on AUTO, or hold them constant at the stock voltage setting when attempting to overclock?

Thanks.

PS. Please correct me if anything I said was wrong. Like I said, I'm a newbie.

July 1, 2008 10:54:26 PM

Auto for lesser over clocks will work fine. PLL, Phase Lock loop, it's how your comp keeps signals clean and at the proper strength.

This can be used for upper FSB over clocks, if you dare!

SB voltage is usually fine on Auto. You may wanna add a notch for a higher over clock.

Don't mess with yer FSB Term voltage unless you need to.

Other than that, your chip will have a x 8 locked multi, I believe. So it will be all FSB x Multi of 8 to get your CPU speeds.

So it will be 450 FSB x the 8 Multi for your 3.6 Ghz.

The CPU speed Range will be controlled by the FSB. Each point you remove will modify the CPU speed by 1 FSB point x 8. So 8 Mhz per FSB point.

So reducing the FSB to 425 would remove 25 points. 25 points x 8 = 200 Mhz. So your speed will be 3.4 Ghz.

Again, take away 25 more, and you are left with 400 FSB. 400 x 8 = 3.2 min that you wanted!

When you gonna get your stuff?

--Lupi
July 1, 2008 10:59:57 PM

I'm getting it tomorrow. today is Canada day so the computer store is closed.

But what is the difference between the Southbridge Voltage and the SB 1.5V voltage? I am assuming SB stands for Southbridge....
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July 1, 2008 11:00:52 PM

just leave it on Auto and dont mess with it. or you will get alot of trouble and need to spend ALOT of time getting the right value to work on your OC.
July 1, 2008 11:01:37 PM

SB is southbridge as you guess. 1.5V just the stock voltage i assume.
July 1, 2008 11:09:43 PM

Kewl, I cant wait to see the VID of your new 45 NM chip!! I hope it is a low one, Come on, one in a million! 1.1000 VID!

Howdy Gill!

--Lupi
July 1, 2008 11:49:54 PM

Hmm. I was looking at the specs of the Asus Rampage Formula, and it says the FSB is 1600/1333/1066/800.

http://www.pcvonline.com/productDetails.aspx?id=6782

Does this mean that when overclocking, the max I can set the FSB is 400? Since 1600/4 = 400 FSB?

So CPU speed = 400 x 8 = 3200Mhz?

Can I exceed 400FSB on this motherboard?
July 1, 2008 11:58:16 PM

Nope. Thats the Rating. Overclocking takes you beyond the rating. However, its mush better to start with a board that fully supports 400 FSB, because you are pretty much handed the ability to go over it. While a 333 FSB board may only OC to 400 FSB.

Anyways, the standards, mean it supports a 400 FSB chip. (The new QX7700s, for instance, are 400 FSB)

--Lupi
July 2, 2008 12:04:34 AM

So when starting my overclock, should I just jump straight from 333x8 to 400x8 or should I slowly make my way up to 400?
July 2, 2008 12:13:18 AM

Since you are relatively new to overclocking, I would start slowly and make it up to your final overclock.
a b V Motherboard
July 2, 2008 12:16:43 AM

I have the Rampage Formula with the X3350(Q9540 Xeon) @3.6 (450X8)


1)Cpu Voltage will very from CPU to CPU start at about 1.3V for 3.6 and see if stable

2) Northbridge will depend on how much RAM you have and what speed, I have 8 Gig and northbridge at 1.5V

3)Southbridge I left in Auto

4) RAM depends on RAM specs. 1.8V to 2.2V. 1.8 is default voltage for DDR2

5) FSB Termination voltage DO NOT GO ABOVE 1.4ishV for to long( AnandTech killed a QX9650 with FSB Termination voltage over 1.4) I have mine at 1.38

A) CPU PLL Voltage - AUTO
B) SB 1.5V Voltage - AUTO

Replace the thermal compound on the Northbridge and southbridge PRIOR to starting up the board. After the stuff ASUS uses heats up its like cement.

Northbridge runs HOT 50C average on the Rampage Formula.

Disable load line calibration for the 45NM CPUs.

Any Qs contact me.

1Haplo
July 2, 2008 12:26:10 AM

Thanks for all the feedback...

The only other thing I wanted to ask for now is about the RAM I got. The Ram I got is OCZ DDR2- 1066mhz.

If I overclock to say 400FSB, that would mean that if I ran my RAM at 1:1 ratio, I would be underclocking my ram to DDR2 - 800mhz.

Is that correct?

Should I keep it at 1:1 ratio or should I use a different RAM ratio in order to maximize the DDR2-1066mhz?
July 2, 2008 12:46:09 AM

The ratio wont matter much after it equals the FSB.

But what if you wanted to get a good Overclock, like 500 FSB or higher? As far as RAM goes, your 1066 will get there easily, and then some, but 800 Mhz junk may not. So stick with what you have.

Unless you dont plan on going further with your Over clock.

Most say they want 3.4, or 3.6, hehe. Then become addicted to the Power!

--Lupi
July 2, 2008 12:51:04 AM

I don't think I'm good enough to get it to 500FSB... I also don't want to melt my CPU.

and then there's that FSB Strap thing I just found out about.. I'm still not sure what to set the FSB Strap at...

Lets say I do get it to 3.2, which would mean the ram would be at DDR2-800. Should I keep it at that setting (1:1) or should I change the ratio to make the ram closer to DDR2-1066?

I think my Motherboard allows me to set the RAM frequency independant of the FSB.
July 2, 2008 1:01:49 AM

It does, but changing it to run higher than the FSB really doesnt do much.

Good enough? Just need a p45 board. 550 is pretty easy from what I read.

But maybe some 4-4-3-15 800 Mhz ram.

--Lupi
!