AMD continues with cold-bug Free CPU – Extreme Bulldozer

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AMD set a new world record during their demonstration to the press last August 31th with a whopping 8.429Mhz CPU-Z World Record.

This is the new undisputed maximum frequency world record and this will be really fun to play with under heavy liquid nitrogen cooling.

Beside this wonderful video, NordicHardware released an interview with Macci :

NordicHardware:“Why doesn’t your CPUs suffer from coldbugs, and will all Bulldozer samples come without it or does this only apply to handpicked samples?”
Sami Mäkinen:
 “I’d need to clarify this from AMD Engineering teams (and not sure if they’d be able to provide much detail to be honest…). But in short (and this is just a personal guess) it likely has to do with the design margins and similar to the Deneb and Thuban CPUs the design appears to be very robust and can withstand even the most extreme cooling solutions. Bulldozer is a very descriptive name in this case.

So far I have not seen a sample that would not run under LN2 – so it looks very promising! I have tested around 10 CPUs so far under LN2.”

NordicHardware:“What kind of voltage did you need to reach your 8.429 GHz result, and how many watts this the system pull?”
Sami Mäkinen:“The sweet spot under LHe cooling and for the CPUZ workload was 2.0125V (CPUZ reported 2.016V). We did not measure the current going to the CPU rail but as usual the CPU power consumption drops dramatically when you move to very low temperatures. For this test the goal was to find out the max. CPUZ result so we didn’t need to load the system heavily. If I’d have to make a guess I’d say we probably stayed within the TDP”

NordicHardware:“How many samples did you have to go through to reach the new world record?”
Sami Mäkinen:“I had pre-tested 7 CPUs in Finland on LN2 and 4 of these hit over 8GHz. We tried one or two of these on LHe in Austin and saw 8.14GHz in the initial tests (temperatures, thermal contact and settings may not have been 100% optimal though). Eventually the CPU that we used for the 8.429GHz run was a random pick from the tray. It was never tested on air or LN2 before. We simply picked it based on the VID value (lower VID usually (but not always!) works the best under LN2). Initial run with LN2 seemed promising so we switched over to LHe and got everything dialed in just perfectly. Temperature dropped down to -235C and we found the optimal voltage level.”

NordicHardware:“It says you reached frequencies “well above 5 GHz” with only air and sub-$100 water cooling solutions. Mind going more into detail about your ventures on air and water?”
Sami Mäkinen“In terms of CPUZ MHz I’ve seen virtually every CPU reach over 5GHz when using a good air/watercooler. I believe the highest result I saw with aircooling was around 5.5GHz CPUZ. This CPU hit around 7.8GHz on LN2.”


NordicHardware:“Also are these 5+ GHz frequencies that could be achieved by people looking for a 24/7 overclock on air or water cooling solutions?”
Sami Mäkinen“There is obviously a delta between “CPUZ MHz” and “24/7 MHz” and overclocking is never guaranteed. But getting close to 5GHz (or even above) on good cooling solutions seems to be possible. Every CPU is different so your mileage can vary.

NordicHardware:“Last, but not least. Any hints or teasers about the FX-series performance?”
Sami Mäkinen:“As mentioned the goal of this experiment was the CPUZ frequency so we didn’t dive in to the world of benchmarking or performance yet.”

Source : Nordic Hardware

And our friends at HardwareCanucks will be releasing an article later tonight about the complete event.


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