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Overclocking Help Needed: Memory Clock

post #1 of 6
Thread Starter 
I am somewhat of a beginner when it comes to overclocking CPUs. I don't buy any special cooling solutions and usually only slightly overclock on air.

I just ordered an Opteron 165 for my ASRock DualSATA board from New Egg to replace my 3700 Sandy which was clocked at 2.65. If I can get the Opteron to that speed I will be happy, which should be easy, in theory.

I downloaded the latest BIOS and can now set my FSB past 274, which will be needed because the best the Opteron can do is a x9 multiplier.

I decided to "practice" a little bit and instead of overclocking my Sandy with the x11 multiplier I decided to use a x9 multiplier and tried to get the speed to 2.65 that way.

The only way I could get the computer to boot is when I really slow down my memory. My memory is 2 GB (2 x 1GB) DDR400 dual channel. I have to take them down to 100MHz (200MHz dual channel) in order to get the computer to boot. I am afraid I will need to do this when I receive the Opteron because of the x9 limit. I am also concerned that memory set that slow will have a performance impact. Is this true? Also, what about the NB and SB settings? Does "auto" = 1000? Will those have an effect on my overclocking? I would rather leave them alone because when I set them to 400 I started World of Warcraft and the computer rebooting while connecting.

Is all of this not really an issue until I receive the actual Opteron? Maybe I should not worry until then? My main concern is the memory, and if is set that low, what type of performance impact is that.

Thanks!
post #2 of 6
You will prob... need to up the voltage. When you up the voltage you will need better cooling. Get some good air flow in the case b4 you up the voltage.
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post #3 of 6
There is a bit of math involved, but we're here to help.

It's good to know that during OC almost all the frequencies change.

MEM speed: take the default value - say DDR400. It is computed as 200x2, where 200 is the HTTx1 and 2 is a DDR multiplier.

OCed mem speed: say you take your CPU from 200x9 to 220x9 for 1980MHz. Ram speed is 220x2=440MHz. If you choose DDR333 in BIOS the ram speed becomes 220x2x333/400=366MHz. Simple, huh? In the formula, 333 is the ram speed you set in the bios, and the 400 is a coefficient.

OCed NB and SB speed: 220x5x400/1000=440MHz The rule of the thumb is you NEED to keep it below 1000, that's why a setting of 400 is exaggerated for this OC. In the formula, 400 is the BIOS setting, and 1000 is a coefficient. If you were to choose in the BIOS 800, the final HT frequency would be 220x5x800/1000=880MHz - better and yet below 1000.

To sum it:
-your sandy at 2.65GHz is at 241HTT
-HT speed if you choose, say 600 in the BIOS is 723MHz
-MEM speed if choosing DDR333 is 400MHz (coincidence )

To get the opty at 2.7GHz you need 300HTT, so:
-lower HT speed to 600 for a total OCed of 900
-lower the ram to DDR266 (133MHz) for a total of 360MHz

There's no need to get the ram at 200 (100) in order to achieve that OC. Moreover there's absolutely no need to put the HT at 400, as it's below 1000 even at 300HTT.

As a side note, I've left mine at 800 and I'm at 350HTT, so 1400MHz, well above 1000. It works on DFIs well, not sure how's working on yours.

Cheers!
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post #4 of 6
Thread Starter 
Thanks I will try that.

Unfortunately in my test when I tried to set Memory at DDR266 (133MHz) I could not achieve a x9 multiplier clock (no boot) that I got at the x11 multiplier clock with that same memory setting.

So....

When a 2.6MHz clock speed works at 11x with DDR266 (133MHz) but fails at 9x with a higher FSB at DDR266 (133MHz) is this a CPU and/or stepping luck of the draw issue or is this a (memory can't handle it) issue?
post #5 of 6
It's most likely a mobo that can't handle OCing very well. The OCing ability of a particular mobo can be found by lowering the CPU multiplier and the ram speed at the minimum, HTT kept below 1000 and then upping the HT frequency.
Decent mobos go around 270 tops. Good OCing mobos go 330, excellent ones go above. This is a subjective way to classify them, but pretty accurate. If you set low multi, low ram speed, HTT is below 1000 and you can't boot, it's only the mobo's fault.
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post #6 of 6
If you have the patience, there is a massive post on that MB.
http://www.overclock.net/amd-motherb...Rock+Dual+SATA
    
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