T_M - Team.AU member Over the weekend i finally got around to some LN2 benching here in Singapore. My last adventure with LN2 was in Gigabyte's Beijing OC Comp on E6550, and i was keen to give it a go now on proper hardware. Still sticking with the P35-DQ6 which i had fully modded for the Beijing competition. Here's my setup: CPU: QX6850 L724A 'G0' Motherboard: Gigabyte P35-DQ6 F5 BIOS thanks Gigabyte Cooling: Mousepot Rev1 Video Card: Riva TNT2 PCI Memory: Crucial Value RAM (D9GKX) PSU: Silverstone 1000W HDD: 500Gb WD AAKS SATAII vCore: 1.83v Real (1.84V load) Board will not boot with higher, but can idle with higher vDimm: 2.5V Real all other voltages at max BIOS settings. CPU definately needs more volts than the board can provide. The day was all about testing my newest family member the QX6850. It had previously shown promise on DICE, but it was clear that DICE couldn't handle the heat load to maintain good benching clocks. Here's a video of my first pull down for the day. Took approx 10mins to reach -120C. Following the pull down, i set about testing for max CPU benchable clocks. Using 32M wPrime on all 4 cores, i bumped clocks starting from 4.8GHz right up thru 5GHz. It was clear i was going to have a good afternoon Next up i set some 32M wPrime and 1024M wPrime times at 5GHz just to get some 'scores on the board' - as any seasoned bencher knows its worth getting at least some scores recorded before something might go wrong. fortunetaly for me, nothign went wrong that day Next up was checking max suicide clocks at 4 cores. And wow, was i ever suprised. 5400MHz without too much trouble at all. And with that under my belt i moved back onto wPrime, one of my favourite benches. Slowly bumping clocks, i edged above 5GHz. That when i encountered what i call 'transition'. Transition While this is not new to other LN2 benchers, it is to me so i'd like to write up my experiences with it. Until now, my LN2 benching had been relying totally on idle temps. Between 32M wPrime runs i had to allows rest time for the system to recover in temps, and during load on 32M wPrime i would lose 10C base temp, no matter if i topped up the pot or not. Mid way thru the session, i decided it was time to head to the toilet, so i topped up the pot with an extra large dose of LN2 and made my way down the passage. From the toilet i could still hear the system and bubbling, but i noticed it get very very loud all of a sudden - so much so that i had to cut my toilet break short to check wtf was going wrong. I returned to find the pot looking completely full to the brim, then just as suddenly it dropped in level again to about 1/5th full (where it should have been). Temps on the pot had dropped crazy low, i think it was -160C when i checked and dropping fast. It peaked at -19xC and sat there for a long time even with the pot empty. Once the pot had finally resumed to a workable temperature, i found that the pot behaved like a totally different beast, holding load was no longer a problem because i could easily move temperature up or down with little pours, and the base no longer lost temp under simple loads like 32M wPrime. Following the session, i spoke to Kinc about my experience and he confirmed it is normal to take a pot down thru this "transition" at -145C or -150C just to change the behaviour of the copper/pot, then once you bring it up again it'll handle totally different! So, being the budding youtuber i captured another transition on camera the next day Be sure to listen to the sound (excuse the background TV) at the tube approaches -152C, then watch the violent change and subsequent "peaceful" rapid drop in temps. Notice also that the bubling changes, before the transition it is larger violent bubbles, after transition it is like a very fine fizz. After all of that, i spent a further 3hrs or so benching my QX6850 on this seemingly strong board from Gigabyte. Cold bug on this chip appears to be around -130C, i can sometimes go lower and it'll survive, othertimes instant hang. Ive even had base temp at -154C while mid bench and it survived. My interest was mainly in 4 core benching, since this chip is a powerhouse intended for some 3D'06 and wPrime damage. I wasnt going for fast scores so my RAM wasn't optimised at all, nor any tweaks. I restarted with my "new" pot down at 4.9GHz, wPrime 32M benching my way right up to 5050MHz, keeping the temps between -120C and -130C with small pours prior to each run. If i found that the temp was going to drop below 130C by the idle after run, i'd quickly hit SuperPI 32M to load up the processor while i did online entry of the score. wPrime 32M http://www.hwbot.org/result.do?resultId=654025 Then at 5050MHz i moved onto a 1024M run, the way the system felt was like it wasn't the max my chip could do, but i was getting itchy feet to get some scores on the board again. Here's a video of my pouring requirements during a heavy loaded 1024M run. As you can see the "new" pot could take whatever the chip could dish out :devil: wPrime 1024M http://www.hwbot.org/result.do?resultId=654083 Next up, i moved onto CPU-Z validation for max suicide with 4 cores. This is where things start to get really cool hehe Looking at the difference between this massive clock and my wPrime max clocks, it was clear to me that the CPU just couldnt get enough volts to power thru 4 core benches. Now for some SuperPI loving (not my favourite bench these days). Totally unoptimised runs, all 4 cores and no affinity: And finally i'll finish of with some Hexus PiFast for the purests: Here's some photos from the day: Stay tuned for big things with this CPU :woot: Thanks for listening. Also, i'd like to thank my fellow Team.AU teammates, Gigabyte, Kinc and Hicookie for all their support and tips and tricks over the last few weeks. And Jason (MickeyMouse) for his great pot still going strong.