An Expansion on Applied Computer Cooling By Spencer Ellsworth LAES 400 November 29, 2012 Abstract In the world of professional technology, many businesses utilize servers and Ap- ple products in their day-to-day work, relying upon these machines for the liveli- hood of their operations. However, the technology being used is limited by a single, ever-important factor: heat. The key to improved performance, increased computer longevity, and lower upkeep costs lies in managing machine temperatures. Previously, this topic was investigated for the world of PCs. In this paper, modifications, upgrades, and available components that improve cooling are discussed in regard to servers and Apple products. Through the use of these methodologies, the aformentioned improve- ments may be achieved. Contents 1 Introduction 1 2 Background 1 3 Servers 2 3.1 Freestanding . 3 3.2 Rack Mount . 3 4 Apple Products 5 4.1 Difficulties . 5 4.2 Mac Desktops . 5 4.2.1 iMac . 6 4.2.2 Mac Pro . 6 4.3 Mac Mini . 7 4.4 Apple TV . 7 4.5 MacBook . 8 5 Business Economics 8 5.1 Servers . 8 5.2 Apple . 9 6 Related Work 9 7 Conclusion 10 1 Introduction freestanding and rack mount servers, as their differences are significant. The topics of \Now this is not the end. It is not even this paper then make a transition to Ap- the beginning of the end. But it is, per- ple products, touching upon the difficulties haps, the end of the beginning." -Sir Win- in improving cooling for Apple machines, as ston Churchill, 1942 well as individual investigations of the iMac, Six months ago, the author completed a Mac Pro, Mac Mini, Apple TV, and Mac- research, analysis, and experimentation pa- Book. Sections on business economics, re- per. Entitled \Applied Computer Cooling," lated work, and the potential for future work the paper ended with the above quote from will help bring context to the technical re- Sir Winston Churchill. In this paper, meth- search and will explain the impact of the in- ods for managing temperatures in PCs were formation that was found. investigated. Over the months since that pa- per's publishing, a number of feedback com- ments and results have pointed to a desire 2 Background for more information on cooling. Specifi- cally, a large number of people were inter- In many cases, businesses use servers as they ested in information pertaining to the cool- are sold, with no modification, following the ing of servers and Apple products. In the initial setup. Yet, the similarities between same way that the original paper was in- a great deal of server architecture and that tended to serve as a guide for users with com- of PCs invite the possibility that cooling puter knowledge at all levels, this work will components for one may be able to be used follow a similar structure of clear and con- for the other, albeit with minor modifica- cise examples coupled with straight-forward tions [15]. To clarify this terminology, com- definitions. While this paper may be seen puter architecture is defined as \the struc- as a standalone work, some concepts will be ture, behaviour, and design of computers" more clear following the reading of \Applied [12]. This, in turn, includes all internal com- Computer Cooling" [16]. ponents, such as the motherboard, RAM, It is the hope of the author that this pa- harddrives, and cooling devices. It is on ac- per will provide the reader with a greater count of these points that the concept of im- depth of knowledge regarding the available proved cooling for servers is, more often than options for the cooling of servers and Ap- not, unrealized and unexplored. ple products. The following information is This same lack of realization may be ap- meant as a broad overview of the available plied to Apple products. An entirely dif- options and not as an exhaustive listing. Ed- ferent culture surrounds Apple and their ucation on these options will lead to better user base, as compared to that of PC users, decision making and increased returns. whether they be Windows gamers, Linux Background information will introduce power users, or simply computer owners, the reader to the topics at hand and the as- who had no desire to pay the typically-higher pects that are being examined. Next, servers cost for a machine based on Apple's Mac will be covered, the research discussing both OS X operating system. This Apple culture 1 tends to settle (not necessarily in a negative completely unnecessary. However, despite manner) for that which is offered and pro- servers being much the same as computers, vided by Apple for their customers. Many for all intents and purposes of consideration, customers are entirely satisfied with their ex- the exception lies in their cooling, because perience and with the usage and function- the primary difference is in their architec- ality of their machines. However, for some tures in most cases. In order to be clear, in more advanced users, questions, regarding this section, the hardware side of a server is unadvertised and greater ranges of perfor- being discussed, as \server" can also refer to mance, have been raised. In addition, some the software running on such a machine or owners of Apple computers simply have the a remote service accessible via the Internet desire for their machines to work better than [11]. when they were first built. The differences between servers and com- In \Applied Computer Cooling," the au- puters may still seem minuscule and irrele- thor discussed primarily air, liquid, and pas- vant; however, servers run for long periods sive cooling. Air cooling involves utilizing of time without interruption, requiring re- fans to push cool air across hot components liable and efficient cooling to be used, es- and/or pull hot air away from components. pecially when it has such a huge impact Often, these components are mounted with on energy consumption. According to the heatsinks and other heat dissipation devices, president of the prominent microprocessor and it is from these devices that the air car- company, ARM, \...servers themselves ac- ries away heat. Liquid cooling combines a count for around 2.5 percet of the US energy passive heat transfer, usually from the cen- bill, and cooling them accounts for as much tral processing unit (CPU) to a plate called again" [4]. Different servers perform differ- the \water block." This water block con- ent tasks, but, rather than get into server nects to a radiator via hoses that shuttle purposes, two main server hardware types, coolant across the block, drawing away the the freestanding server and the rack mount heat. Passive cooling, then, is essentially server, will be addressed, along with meth- a non-electronic utilization of part of these ods of cooling for each. previous two methods. Heatsinks and other The front line of defense for many servers devices for dissipating heat are mounted to against high temperatures is climate con- computer components, and the ambient air trol. This typically takes the form of special carries away that heat, which has been pro- air conditioners for the room in which the duced in the operation of the computer [16]. server is located. As these rooms are typi- These topics will be discussed in the context cally enclosed and sequestered from sight, it of server and Apple computer architecture. is important that they are maintained at a safe temperature to decrease the likelihood of heat-related issues. Airflow throughout 3 Servers the server area and low humidity levels are also critical and can be maintained using The argument might be made by some special cooling equipment meant for use with that a section on the cooling of servers is servers [3]. For small business servers or 2 home servers, a full-sized, special cooling setup. A pump that is powerful enough unit may not be necessary. However, main- to cycle the liquid through the extra tub- taining low temperatures, low humidity, and ing distance added by the addition of one constant airflow should still be a priority, in or more additional CPUs will be necessary. much the same way that this plays an im- Additionally, most waterblocks are not sold portant role in the functionality of desktop with the mounting options for server moth- computers [15]. erboards, which are different than those of most desktop computers. Thus, mounts that 3.1 Freestanding match the server processor type must be pur- chased and used [13]. While this sounds like While a freestanding server may look a lot a complicated process, the returns of perfor- like a typical desktop, the architecture of mance increase and electricity consumption the motherboard itself, as well as much of decrease are worth the effort. the other components, differs in order to support multiple users, etc. Server moth- 3.2 Rack Mount erboards require much more RAM and pro- cessing power in order to handle multiple Rack mounted servers differ from freestand- sources of draw on their resources. Be- ing servers in their physical appearance and cause of this, freestanding servers need cool- how they are stored. Rather than being con- ing options that can handle these differ- tained in a single upright case, these servers ences. Some of the available desktop com- have their components arranged in shallow, puter modifications can be retrofitted to be tray-like cases, which are mounted in upright appropriate for use in a freestanding server. cabinet racks. These servers are especially These include heatsink lapping, heatsink up- utilized, when an organization has multiple grades, and fan upgrades [15]. servers, and space is at a premium [15].