Overclocking

As cooling solutions do a better job of keeping the CPU at a lower temperature, 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 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 Scythe Ninja Plus B with the stock fan could only reach 3.83GHz overclock with stability. This is a little better OC than the OCZ Vindicator with the stock fan and matches the performance of the Scythe Infinity with a single stock fan. It is not, however, performance comparable to the top tier of the heatpipe towers tested.

However a change to the 72 CFM 14 dB-A SilenX IXTREMA 120 allowed us to push the overclock to 3.90GHz with complete stability. This does match the top tier of overclocks achieved by the Tuniq Tower 120, Thermalright Ultra 120/Scythe SFLEX, OCZ Vindicator (with SilenX), and Scythe Infinity with dual push-pull fans.

The only air cooler that has reached higher than 3.90GHz is the Thermalright Ultra 120 Extreme, which was featured at CeBIT. We managed 3.94GHz with that top air cooler. The hybrid TEC/air Monsoon II Lite reached 3.96GHz in benchmarking, but that cooler combines active TEC cooling with passive air cooling and would be expected to reach higher overclocks than an air alone solution.

Noise

For many enthusiasts upgrading cooling the goal is maximum stable overclock, and they will live with the inconvenience of a louder system. For other users silence is the most important factor, and these users will forgo maximum overclocking if that increases system noise levels.

We measured noise levels with the Scythe Ninja Plus B with both stock and SilenX IXTREMA fans under both load and idle conditions. The fans have specified noise ratings of 20.9 dB-A and 14 dB-A, and the measured noise with both fans was below our system noise floor at both 6" and 24" positions above the open side of our system case.

There are virtually no power supplies that do not include a fan. While Zalman and a few others do make an expensive fanless power supplies, we have not seen a fanless unit larger than 500W, or one that would be used for seriously overclocking a system. With that in mind the noise level of the system with all fans turned off except the power supply was measured. The power supply used for the cooling test bed was the OCZ PowerStream 520, which is one of the quieter of the high performance power supplies.

We have also measured the Corsair 620-watt and Mushkin 650-watt power supplies which are reported to be quieter than the OCZ. Both the Corsair and Mushkin are indeed quieter at idle or start up speed. However, as soon as load testing begins and the PSU fan speed kicks up the measured noise level is almost exactly the same as the OCZ PowerStream 520 watt power supply.

We are currently in the process of evaluating "quieter" power supplies for an update to our cooler test bed. We will make changes to that test bed as soon as we are confident in the noise measurements and test procedures with a variable speed quiet PSU. We plan to evaluate additional power supplies and configurations in our upcoming 120mm fan roundup, at which point we will complete the transition to a revised and lower noise cooler test bed.

The noise level of the power supply was 38.3 dB from 24" (61cm) and 47 dB from 6" (152mm). The measured noise level of the test room is 36.4 dB, which would be considered a relatively quiet room with a noise floor slightly below the OCZ PowerStream 520 PSU.

Noise Level - 6

Noise Level - 24

Measured noise levels in this chart should be considered worst case. Measurements were taken with an open side of a mid tower case 6" and 24" from the HSF. Real world would be a completely closed case resulting in a further reduction in noise.

Any 120mm fan that is a standard 25mm thick should be mountable on the Scythe Ninja Plus B. The fan clips connect to the outside mount hole, which means both open post and the more common closed post fans will work properly. The stock Ninja fan is closed post and the SilenX is open post. This means the SilenX will work on any cooler we have reviewed thus far - including the Thermalright Ultra 120 and Ultra 120 Extreme.

Scaling of Cooling Performance Final Words
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  • Frumious1 - Wednesday, April 11, 2007 - link

    RTFA! The stock fans are different, and there's no reason to compare the OCZ with the Ninja fan or the Ninja with the Vindicator fan. If someone is going to but a heatsink and use a different fan, they're a lot more likely to go with... I dunno, maybe something like a SilenX? They used the same aftermarket fan for both non-stock configurations, and the Ninja performed slightly better in the termperature tests. Isn't that the informaiton you wanted???

    I'm sorry (not), but your post is pretty much pointless. Your reading comprehension is flawed, considering the content of the article.
    Reply
  • Brunnis - Wednesday, April 11, 2007 - link

    Way to be on the offensive... I was talking about ALL the heatsinks not just the Ninja vs Vindicator. I've re-checked the article and I've still not found any info on what fans that were used on the other heatsinks. So, apparently I'd have to dig back through all the old tests to find that info. Is it too much to ask for a table that lists the fans (including the RPM) used on each cooler? It still wouldn't enable us to see what heatsink that actually performs the best (with the fan out of the equation), but it's better than nothing. Reply
  • Frumious1 - Wednesday, April 11, 2007 - link

    Ah, I see... you want them to do something like maybe a fan roundup, right? Maybe if you ask nicely instead of using words like useless and pointless they might do a http://www.anandtech.com/casecooling/showdoc.aspx?...">120mm fan roundup? Outside of the Thermalright coolers however, I'd expect just about everyone to go with the stock fan anyway.

    On a different note, I think a nice list of current street prices for the various coolers would be very useful. Most of the cooler reviews have mentioned price, but a table somewhre in the article would make the situation a lot more clear.
    Reply
  • DrMrLordX - Wednesday, April 11, 2007 - link

    Good to see the ol' Ninja alive and kicking. That ought to put any comparisons between it and the OCZ Vindicator to rest. Reply
  • Spoelie - Wednesday, April 11, 2007 - link

    Kinda hard when the label of the table on the second page still says ocz vindicator ;) Reply
  • Wesley Fink - Wednesday, April 11, 2007 - link

    Editing oversight corrected. Reply

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