Overclocking

In the review of the Thermalright Ultra 120, which matched the 3.90GHz highest overclock of the best tested coolers, we concluded that the maximum stable overclock of this X6800 processor on air was likely 3.90GHz. This looked reasonable considering the dual-fan Scythe Infinity, the Tuniq Tower 120, and the Thermalright Ultra 120 all topped out at 3.90GHz. Other heatpipe towers all topped out below this threshold, with the better coolers very close to the 3.90GHz plateau.

We were wrong. Better air cooling was possible and we are seeing what that cooling can do for overclocking in the performance of the Ultra 120 Extreme. It is all about cooling, and as cooling solutions do a better job of keeping the CPU at a lower temperature, then it is reasonable to expect the overclocking capabilities of the CPU will increase.

In each test of a cooler we measure the highest stable overclock of a standard X6800 processor under the following conditions:

CPU Multiplier: 14x (Stock 11x)
CPU voltage: 1.5875V
FSB Voltage: 1.30V
Memory Voltage: 1.90V
nForce SPP Voltage: 1.35V
nForce MCP Voltage: 1.7V
HT nForce SPP <-> MCP: Auto

Memory is set to Auto timings on the 680i and memory speed is linked to the FSB for the overclocking tests. This removes memory as any kind of impediment to the maximum stable overclock. Linked settings on the 680i are a 1066FSB to a DDR2 memory speed of DDR2-800. As FSB is raised the linked memory speed increases in proportion. The same processor is used in all cooling tests to ensure comparable results.

Highest Stable Overclock (MHz)

The Thermalright Ultra 120 Extreme with the Scythe S-Flex fan set a new overclocking record by maintaining a stable 3.94GHz. This is the highest stable overclock we have reached with air cooling with this CPU. We could boot at speeds as high as 4.0GHz, but gaming performance was not stable at speeds higher than 3.94GHz. Increasing the CPU voltage also did not increase stability above 3.94GHz, as 1.60V was the maximum voltage usable without generating random reboots of the system.

The best coolers prior to the Ultra 120 Extreme have topped out at 3.90GHz. The 3.94GHz with the Ultra Extreme was something of a surprise, but it proves again that if you move enough air and use enough heatpipes in a good design you can further improve air cooling. Eventually the limit will be reached with air cooling, since it is not an active cooling solution. Air cooling cannot cool lower than the ambient temperature of the room, and it will therefore be outperformed by some active cooling solution like TEC or phase-change cooling. Water cooling is also limited by ambient temperature, but liquid is a better medium for absorbing and releasing the heat produced in CPU cooling. This is also part of the principal used in the design of heatpipes that are proving effective in the current crop of heatpipe towers.

At a 3.94GHz maximum overclock the Thermalright Ultra 120 Extreme is the best air cooler we have tested at AnandTech. It is clear Thermalright knew what they were doing in modifying the Ultra 120 design with additional heatpipes.

Scaling of Cooling Performance Final Words
Comments Locked

54 Comments

View All Comments

  • DrMrLordX - Wednesday, March 7, 2007 - link

    I can't see many reasons to go with the Tuniq Tower 120 over this thing except maybe for the price. The Ultra-120 and Ultra-120+ both cost more after you pay for the fan.
  • Gigahertz19 - Wednesday, March 7, 2007 - link

    I'll have to look through the article again but what about noise level for the fan? It can be a great cooler but if it emits a lot of noise then it's worthless in my book.


    Any possible chance of reviewing some water-cooling systems for the Core 2 Duo in the future? I'd be curious to see how a cheap water cooling system would compare with a high end cooler like the Ultra 120+? Specifically a $50 water cooler like the Cooler Master aquagate mini or a higher end water cooling system like the Corsair Nautilus 500.


    COOLER MASTER AQUAGATE Mini R80 / R120 Liquid Cooling System - $50 Newegg
    Thermaltake CL-W0065 Liquid Cooling System - $60 Newegg

    CORSAIR Nautilus 500 Water Cooling Sytem $150 Newegg
    Swiftech H20-120 PREMIUM CPU Liquid Cooling Kit $122 Newegg

  • Wesley Fink - Wednesday, March 7, 2007 - link

    The noise is all cases, both Idle and Stress, and High and Low speeds, was at or below the system noise floor which is determined by the quiet OCZ PowerFlex 520W power supply. For a fan with 64 CFM output these noise levels are extremely low. Scythe rates the fan at 28 dbA at full output and our tests did not reveal any results that would bring that spec into question.
  • Wesley Fink - Wednesday, March 7, 2007 - link

    As we said on page 2 the SAME S-FLex fan was used for testing the Ultra 120+ that we used in the Ultra 120 review. THe noise test results are the same as the Ultra 120 review at http://www.anandtech.com/casecooling/showdoc.aspx?...">http://www.anandtech.com/casecooling/showdoc.aspx?...
  • Ender17 - Wednesday, March 7, 2007 - link

    how about some tests with the reference fan at 7V?
    31 dBA is way too loud for any quiet system
  • Wesley Fink - Wednesday, March 7, 2007 - link

    Our OCZ Power Stream 520 is one of the quietest performance power supplies we have tested and it has a noise floor of 38.3dB from 24" (61cm) and 47dB from 6" (152mm) - both measured from an open case side. Noise measurements will be lower with a closed case, so ours should be considered worse case. The measured noise level of the test room is 36.4dB.

    Since you consider 31db to be too loud can you please tell us the power supply you are using for your quiet system and how you measure noise? Distance conditions, ambient room noise, etc. We see no point in measuring noise below a Power supply noise floor since few users will run their systems with a fanless PS.

    You can also run the 120+, 120, or HR01 without a fan for near zero noise, or choose an S-Flex SFF21D fan with 8 DBA noise at around 34cfm.
  • ATWindsor - Wednesday, March 7, 2007 - link

    The OCZ isn't that a quiet PSU, han 36.4 db isn't a paticulary quiet room either. If there is no other equipment in the room, I would even say its a bit high on background noise.

    AtW
  • ATWindsor - Wednesday, March 7, 2007 - link

    The OCZ isn't that a quiet PSU, han 36.4 db isn't a paticulary quiet room either. If there is no other equipment in the room, I would even say its a bit high on background noise.

    AtW
  • Marlowe - Wednesday, March 7, 2007 - link

    I must agree. I sold my 520W Powerstream because it was too noisy.

    I have the Tuniq Tower also, it's a great cooler I agree! =)
  • Ender17 - Wednesday, March 7, 2007 - link

    also, the PowerStream isn't even close to be the quietest PSU available.
    Checkout Corsair or SeaSonic.

Log in

Don't have an account? Sign up now