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LN2 mode for GIGABYTE A85X-UP4 and 990FXA-UD3 (for high Trinity/Piledriver validations)


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As everyone who has tested Trinity and Piledriver before knows, both are very hote when overclocking. In fact, the pot would be boiling even when idling at 7.5GHz and high voltage. Because both architectures are very much temperature dependant when it comes to overclocking, you need to reach as low as possible temperature to get the highest frequency.

 

For the Z77X-UP7, Gigabyte already has an "LN2 mode". This feature is not really "LN2 mode", that's just the marketing name, but is just a simple P-state modification. When enabled, the CPU will be forced to the lowest P-state, which has the lowest CPU ratio. For Trinity and Piledriver, this is more useful than Ivy Bridge as the low P-state will allow for colder temperatures in idle. The way to use the LN2 mode is:

 

- Step 1: go in OS and open CPU-Z

- Step 2: set LN2 mode enabled

- Step 3: set bclk / ratio you want by software

- Step 4: wait for a couple of seconds to reach the lowest possible temperature

- Step 5: disable LN2 mode => CPU will go to highest P-state

- Step 6: important! wait for a couple of seconds in the highest p-state mode (*)

- Step 7: hit F7 to make validation

- Step 8: go back to step2 and repeat.

 

(*) necessary because CPU-Z has 3-second rule for validation requirement. More info: http://hwbot.org/forum/showthread.php?t=30365

 

At the AMD event, Hicookie used LN2 mode to achieve higher clocks than before without the LN2 mode. He was so friendly to share how to do the LN2 mode on these boards ... yeey! It's actually quite simple: link the P-state soldering point to a switch and hook up the switch to gnd. Connect P-state point to gnd to enable LN2 mode, switch to the other side to disable. It's so easy!

 

Example:

 

IMG_20121120_174855.jpgIMG_20121120_174903.jpg

 

LN2 Mode modification for A85X-UP4

 

A85XUP4.png

 

LN2 Mode modification for 990FXA-UD3

 

990FXAUD3.png

 

(ps: maybe another pro-tip. To achieve the lowest possible temperature in idle, don't forget to also reduce the NBclk and lower the HT link and NB voltages ...)

 

// end of sharing //

 

//edit: by the way, they didn't want to share what pin to mod so it's not possible to copy the mod to other boards as well. But, just like with the Clarkdale CB mod, it's just a matter of reverse engineering. Just follow the P-state point to the socket pin and check what the pin is in the AMD reference datasheets. I don't have much time left this week, but I might have a look at it next week. If someone finds it ... please share so we can copy this mod to all boards :).

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Hicookie did the 7.8G validation with it - previously 7.5G. Afaik, they also did some tuning on the digital PWM, but that requires a firmware flash and the tools for that are under NDA :(. Still looking for a way to get that stuff without violating the NDA, though. Hicookie mentioned he got about 50-100MHz with the LN2 mode. The rest comes down to slim XP instead of big W7.

 

[hwbot=2329722]submission[/hwbot]

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Hicookie did the 7.8G validation with it - previously 7.5G. Afaik, they also did some tuning on the digital PWM, but that requires a firmware flash and the tools for that are under NDA :(. Still looking for a way to get that stuff without violating the NDA, though. Hicookie mentioned he got about 50-100MHz with the LN2 mode. The rest comes down to slim XP instead of big W7.

 

[hwbot=2329722]submission[/hwbot]

Figures, The Stilt was able to get 7600 from a 7300 5800K by tuning the PWM. :/

AM3+ platforms wouldn't have such a problem, would they? O.o

 

Nice to see 50 Mhz gain from lower idle temperatures, maybe it's dropping temps about 5-10c

 

EDIT:

Oh derp, he posted in this thread. xD

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