Version 5 (amended and enlarged), Autumn-Winter 2007
Detailed descriptions of cooling systems, thorough analyses of their functionality and usability, test results, etc — they are certainly useful and necessary. But having read hundreds of pages of various reviews and having examined lots of images, a user may fail to find a clear answer to his/her vital question: "Which cooler should I buy after all?"
Indeed, a common drawback of the absolute majority of reviews devoted to cooling systems is an evident lack of unified integrated assessment of functionality and quality of these systems, which would allow to organize all usability parameters and generate informative comparative characteristics of coolers to be clear even to inexperienced users. Of course, you may sometimes run across articles with some charts or ratings. But how these ratings are formed and what objective (subjective) parameters are taken into account — these details are usually a sealed book and known only to the authors. When such "charts" award dubious products, while decent products are left in the bottom of the list, inadaptability of this or that abridged approach to assessing functionality of cooling systems becomes evident.
We couldn't put up with this situation for long. We mustered all our strength and formulated our own procedure for integrated assessment of cooling systems. It is not perfect. But in our opinion, it reflects the real image of a cooler rather objectively.
OK, let's proceed to the essence of our procedure.
In our opinion, any cooling system has seven key characteristics to be evaluated. They are:
Besides, there are two bonus categories:
We also introduce a system of penalties for cooling systems that reveal low quality of their components, insufficient professional fitness or insufficient ergonomics.
To objectificate all these assessments, each of them, except for a professional fitness group, gets a corresponding index, which is calculated (defined) in accordance with the established procedure.
Et = (WF*Rti)/TR (points), where
Et — thermal efficiency index, WF — weight factor, Rti — reference thermal index (reference thermal resistance θja), TR — thermal resistance θja of a given cooling system.
Reference thermal resistance is: 0.30°C/W for coolers for AMD Socket 754/939/AM2 and 0.25°C/W for Intel LGA775 devices (these are the best results considering modern technological capacity for mass production). Weight factor is 90.
N = (WF*Rn)/NL (points), where
N — noise index, WF — weight factor, Rn — reference noise index, NL — noise level of a cooling system.
Usability of active components (U AC) and usability of a retention module (U RM)
Unsatisfactory — 0 points
There can be intermediate scores. For example, 29 points can be interpreted as "this fan is of excellent quality, but colors of its wires are too dull (the retention module is wonderful, but its mirror surface does not reflect user's face well enough)". One point — "the fan is of terrible quality, but it can still clatter along for several hours (the retention module actually damages a CPU core only during the second unsuccessful attempt to install a cooler)".
Usability of passive components (U PC)
Unsatisfactory — 0 points
Professional fitness level
A level of professional fitness is expressed by belonging to a "professional fitness group" (PFG) that includes certain types of processors, ranked by TDP.
We define the following PFGs for AMD (Socket 754, Socket 939, Socket AM2):
The following PFGs are defined for Intel LGA775:
Professional fitness group of a processor is determined like this:
Ep = (WF*Rp)/P (points), where
Ep — price efficiency index, WF — weight factor, Rp — reference price, P — average retail price of a cooling system.
Reference price of a cooling system for AMD:
Reference price of a cooling system for Intel:
Professional Fitness Group C (AMD) — 25 points
Thermal efficiency below PFG A — IAF CS is reduced by 10%
All indices and bonuses are given to cooling systems according to their test results and published in a technical-economical chart. The sum of all indices and bonuses (after penalties, if there are any) gives us the integrated assessment of usability of a cooling system (IAU CS). If we don't take price efficiency (attractiveness) into account (for example, to evaluate pure functionality of a cooler), then we should calculate the integrated assessment of functionality of a cooling system (IAF CS). Then we sort IAU CS and IAF CS results to form a table of ranks — economical and usability ratings of cooling systems.
These are the key points of our new procedure. We hope that our procedure will help our readers solve a problem of choosing a cooling system to meet their requirements to quality and functionality. In conclusion we'd like to say that your constructive comments and suggestions are welcome!
Vitali Crinitsin (firstname.lastname@example.org)
November 26, 2007
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