X4 955 Oc Help

[lopri]

Run CPU-Z and check the stepping. Also, if you bought a retail processor, you can look up the model numbers.

http://products.amd.com/en-us/DesktopCPUSideBySide.aspx?id=532&id=682&id=618

 

[jay2nice000]

Thanks for the info very useful

 

[lopri]

One mis-information in my post above. I looked up my old screenshots and the C3 955BE (pre-Thuban) took 1.5V for 4.0 GHz, not 1.4V. 1.35V for 3.8 GHz.

 

[soccerballtux]

Thanks for the info very uses

haha

 

[jay2nice000]

There are at least 3 different 955s/Denebs as far as I know.

C2
C3 pre-Thuban
C3 post-Thuban (rare)

C2's are obviously the worst, and their sweet spot is probably 3.6 GHz, although 3.8 GHz was not too difficult. These are the ones with the infamous 4.0 GHz ceiling under 64-bit Windows.

I had a brief experience of C3 pre-Thuban 955, and it did about 200 MHz better. (3.8~4.0 GHz) Same ~1.40 vCore. In general voltage isn't a limiting factor for these chips, but the temperature is. It helps a lot if you have some air flow around the VRMs/Mosfets.

I don't have a first-hand knowledge of post-Thuban 955s, but apparently AMD has made some changes to the silicon substrate and these behave much like Thubans, meaning these 955s are way better than previous ones. (Not talking about 960T which IS a Thuban) Don't quote me on this, though, it's a hearsay.

Which one you have is a luck of draw, especially for the different C3s. I think most of 955s in the market are pre-Thuban C3.

ok just check i guess im one of the lucky few my chip is RB-C3. if i have one of the best 955 how come i cant push 4.0 with easy

 

[Leyawiin]

ok just check i guess im one of the lucky few my chip is RB-C3. if i have one of the best 955 how come i cant push 4.0 with easy

Every chip is different regardless of stepping. Sometimes you win the lottery, some times you don't.

 

[jay2nice000]

Every chip is different regardless of stepping. Sometimes you win the lottery, some times you don't.

well to start off im a noob when it comes to oc but i did figured something out i turn up the multiplier to 16.5x and bump the voltage to 1.425 running at 4.0 with out touch my ram ddr3 at 1600. ran prime95 but it keeps failing then ran it with amd overdrive for 3 hours and ran stable temps idle where 35c and 50c under full load without a problem. running CM sniper 3x 120m fans on stock heatsink. i dont know how to mess with fsb and all that other stuff. i tried doing some research but came up empty handed. do you think my set up is good or if i could push it more with messing with other stuff like fsb and so on and forth?

 

[soccerballtux]

ok just check i guess im one of the lucky few my chip is RB-C3. if i have one of the best 955 how come i cant push 4.0 with easy

I think you bought a chip after they've started binning higher.
IE they haven't changed their process or anything, yet they released a Ph2 x4 975.
A portion of 965s that would have made great overclockers became 975s,
and a portion of 955s became 965s,
and a portion of (something worse) became 955s.
and you probably got one of these.
Or maybe they just started binning up the 955s to 965 with the intention of not selling as many 955s.

I have to say I was a little disappointed that I couldn't hit 4.2ghz with my 965..