Scaling of Cooling Performance

The Thermalright Ultra 120 Extreme has been the top performer so far in CPU cooling at stock speeds. As overclocks are raised, the Ultra 120 with the Scythe SFLEX fan maintains its cooling advantage. The Scythe Ninja Plus B is average in cooling efficiency with the stock fan. However, a swap to the specified 14 dB-A/72 CFM SilenX fan improved cooling to the levels of the top tier heatpipe towers in our reviews.


At 2.93GHz the retail HSF is running at 41C, compared to 31C with the Scythe Ninja Plus B with the stock fan.. This is a delta of 10C. The SilenX drops that temperature to 27C, or a delta of 14C. The delta with the stock fan remains about the same as the overclock increases. At 3.73GHz the idle with the retail fan is 56C compared to the Ninja stock at 47C - a delta of 9C. Performance improvements are much greater with the SilenX fan on the Ninja Plus B. At 3.73GHZ the SilenX cools to 36C, while at the highest stable overclock of 3.90GHz the Ninja/SilenX is at 42C. This almost flat line at idle at the top of our testing is an indication the SilenX is effectively cooling at idle all the way to the top speed that could be reached in benchmarking.

Cooling efficiency of the Ninja Plus B, with stock and SilenX fans, was next tested under load conditions. Results are compared to the retail HSF and other recently tested CPU coolers. The Scythe Ninja Plus B with the SilenX fan generated results almost identical to the Scythe Infinity with Push-Pull fans and reached the upper tier of overclocking performance. Results with the stock fan were average.


By 3.90 GHz - the highest overclock the Tuniq, Thermalright Ultra 120, OCZ Vindicator, and push-pull Scythe Infinity could reach with stability - the Ninja Plus B is at 62C with the SilenX fan. This is still worse cooling performance than many of other top coolers at this speed. Push-pull SilenX fans lower this only a couple of degrees more - to 60C. The Tuniq and Ultra 120 are both at 51C, which is some 9C to 12C lower than the Ninja Plus B. However, the Scythe was completely stable at 3.90GHz with the SilenX fan even though it ran a bit warmer. The single stock fan could only manage 3.83GHz so the SilenX or dual Sythe low-noise fans in push-pull configuration are much better fan setups for overclocking the Ninja Plus B.

As stated many times, the overclocking abilities of the CPU will vary at the top, depending on the CPU. This particular CPU does higher FSB speeds than any X6800 we have tested, but the 3.9GHz top speed with the top tier heatpipe towers is pretty average among the X6800 processors we have tested with Tuniq cooling. A few of the other processors tested with the best air coolers reach just over 4 GHz, but the range has been 3.8 to 4.0GHz. Stock cooling generally tops out 200 to 400 MHz lower, depending on the CPU, on the processors tested in our lab.

Cooling at Stock Speed Overclocking and Noise
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  • Lord Evermore - Saturday, April 14, 2007 - link

    How is the Ninja and Infinity "not particularly great for overclocking", when even with their stock fans, when they can hit 3.83GHz? 3.9GHz is only 66MHz higher, a whopping 1.7% higher. Individual CPU differences could easily make that up for other users, and the "better" coolers might not get an equal increase in their maximum speed in those cases. At those levels to me things seem for all intents and purposes essentially equal.

    With the stock fan that's a 31% overclock at 3.83G. 33% at 3.9G. Only in comparison to the very best you've tested do these come out near the lower end of the scale. Right at the end you group it together with the top tier of other coolers. And even if it was at the lower end of the "good" coolers, stock or overclocked, the actual numerical differences are so tiny as to be statistically insignificant.

    I suppose 66MHz difference is a HUGE deal to rabid overclockers who are willing to spend money for it, but the majority of even enthusiasts I'd think wouldn't consider it particularly impressive given how large the stock fan overclock is. (Note I'm only addressing the frequency obtained since that seems to be the focus of what makes a cooler "good" here. Temperatures obtained at those speeds could change the lineup.)
    Reply
  • Wesley Fink - Monday, April 16, 2007 - link

    We use the exact same CPU and test bed for testing all coolers - to remove the "individual CPU" variable. But you are right to put the performance results into perspective. In the grand scheme of performance the difference in 3.83GHz and 3.90GHz is very small as you point out. There are other advantages to the very top performing coolers, however. If you check the cooling at various temps those that do 3.90GHz easily also generally provide the lowest CPU temperaturesa at any given speed.

    Had we devised our overclocking test a little differently and tested say, every 266 MHz - 2.93GHz, 3.2GHz, 3.466GHz, 3.633GHz, 3.80GHz, 3.966GHz - the true differences might be put in better perspective. However, we started the test with the assumption that if a cooler couldn't outperform the Intel Retail there was no point in buying it. Perhaps if the Intel Retail HSF were poorer we could show more, but the fact is the Intel Retail HSF is really very good and it takes a decent cooler to beat the one that comes at no additional cost with the Intel processor.

    Your comments are fair, but we also believe our cooler test methods do identify the very top performers in the marketplace. One notch down is still pretty remarkable performance as you point out.
    Reply
  • strikeback03 - Thursday, April 12, 2007 - link

    It is kind of hard to tell in the photos, does one set of 3 heat pipes run above the other set, or are they somehow woven together so they are all approximately the same distance from the CPU? Assuming they are mounted with one set above the other, did you do any testing to see whether cooling is better with the fan mounted on one side or the other (i.e. blowing directly on the upper set of heatpipes or the lower set). Reply
  • Wesley Fink - Friday, April 13, 2007 - link

    one group of 3 heatpipes passes through an upper plate and the other three pass through the mounting plate below. As you guessed they do cross over the lower set of heatpipes in the center of the base. We did not test with different orientations relative to the heatpipe level, but it is an interesting question. Reply
  • Wesley Fink - Thursday, April 12, 2007 - link

    We have received the following statement from Scythe regarding the similarity of their Ninja Plus B Cooler to the OCZ Vindicator:

    "Scythe is a stock holder of the factory where we produce our coolers,
    and also the factory is a stock holder of the Scythe Taiwan office where
    we have a very tight relationship almost as close as a group company.
    Within this relationship we are acknowledged and aware of all shipments
    done from the factory. But OCZ is not one of them.

    With the above said, we are definitely sure that OCZ coolers are manufactured
    in another factory. The only components that are common between the two are the
    hex caps on the heat pipes, which are supplied outside of our cooler factory.

    We also have not approved OCZ's design in any form or shape, nor did we receive
    any OEM request. Their products are just a simple copy of Ninja and we are
    currently being troubled by this untrue rumor. "
    Reply
  • Lord Evermore - Saturday, April 14, 2007 - link

    My thought is maybe they use a different working fluid. They're just too similar in design for the hardware to have any performance difference, even if OCZ did just copy the design (if they had though, you'd think Scythe would be suing). I suppose the exact alloy composition for the base plate or other parts could be different, if they actually are made somewhere else, and then the parts just end up looking the same and being assembled in the same shape.

    Then again, Scythe doesn't say NOBODY gets this design but them...
    Reply
  • ceefka - Thursday, April 12, 2007 - link

    On the packaging of the Ninja it says: "supports fanless model". Now that of course will be dead silent, but it will require adequate airflow in the form of case fans. What are the temperatures and dBs in that situation? Reply
  • Wesley Fink - Thursday, April 12, 2007 - link

    Fanless cooling seems to perform best with a PS with a downward facing exhaust fan and excellent case entry and exhaust cooling. Our test case does not really have these features, but we will definitely be paying more attention to airflow and the PS fans in choosing components for our new test bed. With the current configuration in mind, it seemed unfair to test fanless mode temps with a poor configuration for fanless cooling.

    We did run a quick 5-minute gaming loop at the X6800 stock speed with a fanless Ninja Plus B and it ran fine. Temps were much higher than fan configurations just as you would expect. We will be doing more in testing fanless claims in the future - once the fans are selected from testing and the new test bed is launched.

    We do confess concerns over fanless given the current crop of excellent perfroming tower coolers. It appears fanless just moves the fans from the cooler to the case, but fans are still required. There are many large quiet case fans, but there are also many quiet 120mm fans for coolers these days. Fanless seemed to make more difference when ccoolers used buzzy loud 60mm and 70mm fans. These days the best coolers use heatpipes and 120mm fans and the noise levels are MUCH lower with these coolers than the screaming wonders of the past.
    Reply
  • fic2 - Thursday, April 12, 2007 - link

    I am curious about the Noise Limit heatsinks: http://www.noiselimit.com/index2.asp?id=16">http://www.noiselimit.com/index2.asp?id=16. Any chance this will be included in a review? Reply
  • Stele - Wednesday, April 11, 2007 - link

    I'm not sure if this question has been dealt with before - my apologies if it has.

    I've always wondered how is it that a certain cooler can produce lower CPU temperatures but yet fail to make it at a higher CPU frequency? The Zalman CNPS9700 is a good example - at 3.83GHz the CPU runs at 40°C, which is lower than many of the others, yet does not make it to the last two CPU frequencies. A Scythe Infinity dual, however, registers 44 at the same frequency and yet makes it at least into 3.90GHz. The anomaly is even more pronounced in the stress test. In all cases the coolers seem to scale similarly, so it's not as if one of them had reached its design limit (compared to, for example, the stock Intel HSF). Has an explanation for this been given or proposed before?

    I'm guessing that one factor is the mounting method. It's remarkable that some Socket-775 coolers, despite weighing some 1.5-2x that of the official 450g limit with fan, still use the stock plastic push-pin method. Without a backplate. Makes one wonder sometimes whether the cooler is indeed in good contact with the CPU, and whether after some time the cooler would fall out - or the motherboard flex and crack.
    Reply

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