I'm surprised SPCR had trouble getting hold of a new D12SL-12,jab-tech.com & nexfan.com carry them (cheap!).
This is more an issue of time than supply. I didn't want to delay the article yet another two weeks while we waited for new samples to arrive and be tested.
There's a couple of hidden issues here I think. First and foremost is the issue of back pressure in our test box. Different fans deal with back pressure differently; some drop significantly in speed, while others barely budge. I think I mentioned somewhere that the worst-case drop was ~200 RPM at full speed.
However, we do not measure RPM with the fan installed in the airflow box. This was done to counter potential issues with people asking about bad samples when our measured RPM conflicts with the rated RPM, which has occurred in the past. This means that the fans that drop the most under pressure have an unfair disadvantage in a straightforward RPM:CFM analysis. As a result, I had to allow for a rather wide margin of error when I did my analysis, especially for fans that I knew were affected by pressure.
The second issue is that my evaluation was based on more than just the data at 25 CFM. My comparisons were done based on average RPM:CFM ratios across all measured points, with a slight emphasis on CFM at ~1,000 RPM, since this is one of the points we looked at when we re-evaluated our test method. This identified the Enermax and Arctic fan as having low airflow, and, looking at the data again, I probably should have flagged the Global Win as well.
While the SilenX did do well in my analysis, it didn't stand out the way the Arctic Cooling and Enermax did. Given the large margin of error I was allowing myself and the problems that arose the last
time I recommended a fan on the basis of high airflow, I didn't feel confident that the data supported concluding that the Ixtrema was necessarily higher airflow.
That said, I did get the impression that it might have been a little better, which I why I made the comment about pressure in the first place, and recommended experimenting. I'm not confident that our data is conclusive, but I do think that further testing and analysis might bring a difference to light. Of course, the issue then is whether the difference is big enough to make a practical difference...