• They are more flexible i.e. easier to work with.
• They look neater within your case.
• Flat cables tend to interfere badly with airflow, rounded cables offer alot less interference.

• They are tricky to make the first couple of times and you may well waste a couple of cables.
• They can cause increased electrical interference in the cable, hence reducing your acheivable data rate. This is enough to put many off but for the lower bus speeds (ATA33) this doesn't seem to be a significant problem.

Reference:

• 7volts.com cable rounding
• Wrapping rounded cables with foil tape- storagereview.com forums -- Ars Thread on the same subject
• systemlogic.net Round cable performance analysis

• Ars thread on this topic
• overclockers.com "A Cool Fool: Part II--No Mo' Fool"
• AMDMB.com thread on temperatures and socket placement

1. Quiet, but effective - Taisol CGK760092, Taisol CGK742092 is ok (older all-aluminum version)
2. Reasonable noise, but better performance - Alpha PEP66t with standard fan (YS Tech, Sunon, or Delta thin fan- 20~30cfm), SVC Golden Gate/OCZ Gladiator with standard fan (e.g. Young Lin Tech 30cfm)
3. Loud as hell, but best cooling for not quite insane money - Alpha PEP66t with 7000 RPM fan, Coolermaster CB5-6G52, Globalwin CAK38
4. Also loud as hell, but getting cheaper than the ones below and just about as effective: the OCZ Gladiator/SVC Golden Gate with Delta38cfm or YSTech 40cfm fan. Not quite as effective as the heatsinks below in performance/noise due to smaller surface area...
5. Costly but very good, Thermalright SK6 w/Delta 38 or YSTech 40cfm fan, Thermaltake Volcano 7+, Millenium Thermal Glaciator II (very quiet for the performance!), Thermalright AX7 (also quiet for the performance!)
6. Expensive, but best cooling - Swiftech MCX462A, Alpha PAL8045. It is only marginally better than the heatsinks in the category immediately above. Not worth the price to upgrade in many people's eyes

P4 cooling is progressing. overclockers.com and a few other sites have good roundups. Alpha's PAL8942, Swiftech's MCX478, Thermaltake Volcano 7+ are among the top. AVC Sunflower is a good lower-end cooler; the stock Intel cooler is actually very good.

For Slot 1/Slot A cooling, the best heatsinks still appear to be from Alpha Novatech-- the P3125 for P3's and P7125 for Athlon's. Loaded with two YSTech or Delta fans and you simply get incredible air cooling short of anything the size of a dictionary book for your heatsink (a la Swiftech). Globalwin's VOS32 is also excellent, but not quite as good. Cheaper coolers are available from Vantec and others and are adequate as well.

The Alpha PAL6035 is not recommended above, simply because it isn't as good as the Alpha PEP66. It will probably fit on more motherboards since it has a top mount (vs. side mount) fan... but numerous other heatsinks are very good now, just as good as the PAL6035 and PEP66. When outfitted with the Delta 38cfm fan, the PEP66 still holds its own against the competition, while the PAL6035 does not perform quite as high.

Reference Material:

• Anandtech September 2001 Socket A Cooler roundup
• Accelenation 11 HS/F test- July 2001
• HardOCP- November 2001 Cooling Roundup
• HardOCP- August 2001 Cooling Roundup
• HardOCP- June 2001 Cooling Roundup
  
• HardOCP- May 2001 Cooling Roundup
  
• HardOCP- March 2001 Cooling Roundup
  
• HardOCP- January 2001 Cooling Roundup
  
• 2cooltek.com - Socket cooler tests
  
• Overclockers.com - Socket Heatsink Recommendations

1. SDRAM- your normal PC66, PC100, PC133 stuff does not need cooling. It will not benefit from cooling except in extraordinary situations.
   
2. DDR SDRAM- your normal PC1600, PC2100, and now PC2400 ram is unknown-- results so far show it runs cool and does NOT need cooling.
   
3. DDR SDRAM on video cards- does seem to make some gains from cooling, but its much higher effective clock rate (usually up to 250mhz DDR, or 500mhz effective) is the difference here.

• Net Express Power Supplies and scroll down for information...
• AAPS Typical PC component power draw list
• Anandtech- AMD Athlon Buyer's Guide - Part 4: Power Supplies
• Understanding and Troubleshooting the PC Power Supply - realworldtech.com

Question courtesy of The Racksasha.

Your heatsink fan should blow the way it came from the manufacturer on your CPU. With the exception of a few new heatsinks (most Alpha Novatech designs and the Hedgehog 238M are notable exceptions), that means the fan should blow air onto the CPU!

You can try what works best on your system, but most heatsinks do not have shrouds to direct airflow effectively for sucking, although some might work better with airflow being sucked away from the heatsink. Heatsinks such as the Alpha PAL6035, Alpha PEP66, HedgeHog 238M, are examples of heatsinks that come with shrouds and are designed to have airflow sucked away from the heatsink.

Most other heatsinks work best (or only work, depending on the fan setup) with the fan blowing down on to the heatsink. This includes heatsinks from Globalwin, Thermaltake, Agilent, Coolermaster, Vantec, and others.

Also, case airflow is very important to heatsink performance. You may want to flip your fan or fans so they cooperate with each other, including your heatsink fan. It depends strongly on your case. Again, YMMV.

As the slot interface is slowly dying out at the moment, the choices for best heatsink haven't changed in the last year or more.

• Alpha P3125 for Pentium II/III Slot (SECC2) packages is considered the best by many.
• Alpha P7125 for Athlons and Pentium II (SECC1) is a minor modification of the P3125 to fit some early Athlon motherboards. These two heatsinks from Alpha are considered the best available, especially when fitted with YSTech 26cfm or Delta 38cfm fans.
• Globalwin VOS32 is the next recommendation. It too can be loud, but it is a monsterous cast heatsink. Equipped with the same YSTech fans as the Alphas, performance is extremely close.
• Vantec P3-5030 is only an adequate cooler.
• Thermaltake SECC2 Orb is somewhat better than the Vantec, but is still only adequate.

Attaching heatsinks to non-stock CPUs (e.g. heat plate removed, outer casing removed, etc.) is not covered here and affects performance as well. The copper-bottomed Alphas should still retain the best performance when attached directly to the core, although we have not yet searched for such information.

2cooltek.com Slot Heatsink Tests
Information on Alpha fitments.

Disclaimer: I have had some materials science education but am not a materials science engineer. Contributions and feedback from others who are more knowledgeable is always appreciated and will be credited accordingly.

It generally comes down to copper or aluminum. Silver is slightly better than copper, but it is such a small difference that it's not worth the cost is the general consensus. Silver's only real signficiant advantage in terms of thermal efficiency over copper is marginal at best. However, given the significant additional cost and minimal performance gain otherwise, silver generally is not worth it.

From a pure performance standpoint, copper is better than aluminum.

Disadvantages to copper are its weight and that it is hard to machine versus aluminum. Examine the copper heatsinks today. Not a single one (Hedgehog 238M, Globalwin CAK38) except the Zalman fan-sinks approaches what has been done with aluminum sinks such as the Globalwin WBK or the aluminum/copper based Alpha PAL6035 and PEP66. Also, copper heatsinks suffer from oxidation which can degrade efficiency slightly.

Aluminum's key advantages are that it is ligher than copper, easy to worth with, and that it is cheap. Very cheap. Other than that, it is an inferior material for heatsinks and coldplates. For information on specific thermal conductivity tables, see the links question up above.

Reference:

• Spiv's heatsink physics article on www.pc-workshop.net
• overclockers.com- Cooling - An In-Depth Look
  
• EDUCATED... aluminum vs copper, etc...
  
• Argh! People keep posting bad physics!
  
• Not specifically on heatsink material- Thermoengine design then heatsink design
  
• "Aluminum releases its heat faster" myth!!!
  
• Finite Element Analysis and Heat-Spreaders/Coldplates (pics) by gearhead86 on Ars.
  
• MIT - Thermal Properties of Materials
• Here we go again! Al releases heat faster than Cu myth... October 2001)

Linkage.... from HardOCP and others.

• Hardforum- Acrylic Case HOWTO+PICS
  
• Case MOD @ Reality.net

Sellers of clear cases.

• clearpc.ca
• clear-viewtech

This particular post is starved for information and will be added as needed/found...

• Arc Welder: type of welder
• Arcing: electricity bridges a gap, usually denoted by a "popping" sound. Generally bad news.
• Cap: Capacitor. Stores voltage to increasing levels until either hits its "capacitance" or is able to discharge into something (like wandering fingers.) Most dangerous thing in power supplies because they can hold power after the PSU has been unplugged.
• CCF, C&CF: Case and Cooling Fetish
• CF: Compact Flash
• CFM: cubic feet per minute. Measurement of fluid movement; usually airflow through fans
• CPU: central processing unit (commonly known as "processor"). Not the same as a computer
• EL: electro-luminescent; usually cable that lights up upon electrical charging
• EMF: electro magentic frequency
• EMI: electro magnetic interference
• FD: Floppy Disk [drive]
• FDD: Floppy Disk Drive
• GPH: Gallons per Hour. A measure of the pumping power of a water pump
• HDD: Hard Disk Drive
• Hose Clamp: a device that attaches to the outside of a hose, used to firmly attach a hose to a fitting
• HS: heatsink
• HSF: heatsink/fan
• I.D.: Inside diameter, commonly used to describe the internal diameter of pipes and tubing
• Inline Pump: A type of water pump that does not need to be submerged in water. Instead, the pump uses an intake hose to feed water into it.
• IR: infrared
• Lapping/Lapped: Sanding a heatink to be as flat as possible to provide maximum contact area.
• LCD: liquid crystal display; small display screen
• LED: light emitting diode; like the little lights used to show hard drive activity
• MIG: type of welding. Gas metal arc welding-- very common type of welding. Easy to learn. See here for more.
• Mobo: motherboard
• mod: Modify
• Molex: Type of connector/plug used to provide power to devices inside a computer
• O.D.: Outside diameter, commonly used to describe the outer diameter of pipes and tubing
• Peltier: See TEC
• Pot: potentiometer. Used to regulate voltage based on resistance (sometimes known as rheostat)
• PSU: power supply unit
• Reservoir: In a water cooling system, the reservoir is a container filled with coolant
• RF: radio frequency
• Rig: complete computer
• SLURP: sensor/LED user readout panel. Homemade tempurature monitor w/LEDs
• Submersible Pump: a water pump that needs to be fully submerged in liquid. A submersible pump is usually housed inside a reservoir.
• TEC: Thermo Electric Cooler. Electrically moves heat from one side of the plate to the other. Also called Peltier for inventor of principle that drives it.
• Tie Wrap: small plastic thing used to hold stuff in place. Usually not removable without destroying the tie. All plastic, completely non-metallic to be safe for computer use.
• TIG: type of welding. Tungsten Inert Gas Welding (Gas Tungsten Arc Welding (GTAW)) is the strongest type of welding commonly used. See here for more.
• TIM: Thermal Interface Material. Those funky yellow pads that you find on some heatsinks.
• Water Block: The water cooling version of a heatsink. A water block mounts onto the CPU in a similar fashion to a heatsink, but uses liquid rather than air to cool the CPU
• Zip Tie: See Tie Wrap

Mid towers:
Some are pretty tall- up to 21" or so...

• Antec SX830, SX1030, KS-282
• Addtronics 6896a
• CasEdge's revised LX734A (w/92mm fan in back)
• Chenbro Genie, Junior
• Coolermaster ATC-200, ATC-201SX
• Enlight's revised 7237 (with 80mm fan in back)
• In-Win S500
• Lian-Li PC60 (and cousins, especially. revised models)
• Lite-On FS020 (TX060, TX800, TX600 are unknown but look passable)
• Soldam WiNDy cases (some look very impressive)
• Palo Alto PA810

Full towers:
Most are >24" tall except the cube servers, which vary in height.

• Addtronics WTX-8500, 7896a (Addtronics probbaly makes the Supermicro SC-750A and SC-760A, it is personal preference)
• Coolermaster ATC-310
• Chenbro ECHO, NET, ULTRA
• In-Win Q500/Q500N
• Lian-Li PC70

Cases to avoid
(for cooling, size, construction quality, or other reasons- most are just outdated designs and may work quite well still):

• CasEdge's original LX734A (aka 3400T): nice case, insufficient cooling
• In-Win A500 (nice construction, but cooling is insufficient for today's systems)
• PSI 917J (crap)
• Enlight's original 7237 (original version was decent in its day much like the A500, today it needs more cooling)
• Antec KS-280 (also Supermicro SC-701A) (nice construction, outdated design)

You will doubtless note some cases aren't mentioned in any detail, or even mentioned at all. Information on those cases may be scarce, there may not be enough reviews on it, we may not have an opinion on it, etc.
This list is NOT all-inclusive and is not meant to be.

• Ars Forum: Inlining fans revisited
• Ars Forum: Custom Turbine Fans?
• Overclockers.com: Fan Stacking: Myth vs. Reality

Note that current AMD Socket A and Intel FC-PGA CPUs all have exposed cores, unlike previous chips which were covered in metal (Intel PPGA, AMD K6) or ceramic (Intel Pentium, Intel/AMD 486, etc).

This is supposedly for improved cooling, but as AMD has found the CPU cores are more fragile than they seem and can be damaged easily.

Intel has thus reintroduced the IHS (integrated heat spreader) to improve CPU cooling. Whacked (crazy), is it not? When you think about it, however...

1. Most heatsinks use a copper base for best performance.
2. The IHS is composed of copper (nickel-plated)
3. Thermal grease application is very important.

With #2, a copper heat spreader is already there so it's less critical for a heatsink to have a copper base. It still is very beneficial. With #3, the thermal grease application is not as critical either, which is vital to OEMs and mass-market consumers.

This is all debatable and ultimately the IHS may hurt cooling, but how much it hurts cooling is very questionable at this time, since only experienced overclockers usually take advantage of the exposed CPU core and copper-based heatsinks to squeeze the extra 0~5C of temperature improvement from careful heatsink preparation and installation.

Some discussion.
1000mhz PIII and it had a heat spreader on it!

This type of reaction happens between copper and aluminum. The copper "steals" electrons from the aluminum, causing the aluminum to deteriorate. This type of reaction can be a concern in a water cooling system where some of the components are aluminum and some are copper (for example an aluminum radiator and copper water block). Even though the aluminum and copper may not be in direct contact with each other, the water in the system will conduct the electrons from one component to the other.

So how to avoid this? Well, there are several approaches you could take:

1) Use components that are all made of one metal. For example, using a copper water block with a copper-core radiator, or using an aluminum water block with an aluminum radiator.

2) Mix an additive into the water to avoid corrosion. Making a solution of 75% water and 25% automotive antifreeze should help things considerably, although it probably won't stop corrosion completely. Also note that Redline Water Wetter does NOT provide adequate corrosion resistance.

3) Use a coolant other than water. You could use a coolant that is not electrically conductive. Since such coolant does not conduct electricity, it will not carry the electrons from the aluminum to the copper, and the cathodic reaction will not take place. The two most common alternatives to water are alcohol and mineral oil. Unfortunately, alcohol is very volatile and evaporates at a high rate, making it an unsafe coolant. Mineral oil doesn't conduct heat very well, which makes it a poor coolant as well.

4) Place a sacrificial anode in your reservoir (assuming you have a reservoir). You can find sacrificial anodes at most auto parts stores. Basically, what the sacrificial anode does is to "divert" the cathodic reaction. Instead of the aluminum giving up its electrons to the copper, the sacrificial anode will give up its own electrons to the copper, thus protecting the aluminum. However, the sacrificial anode will deteriorate over time and will have to be replaced every so often.

A fan duct is a tube, box, or other enclosed connection for a fan to either intake air or exhaust air from a remote opening. They are often used to direct air from a fan to a specific point inside or outside a case. It's hard to describe, and easier to visualize.

Effectiveness is tricky to determine-- many situations where hot air from a CPU or video card is immediately exhausted out of a case via a fan and duct can be very effective, but ducts can also block internal case airflow. Do experiment before going overboard.

References:

After learning a bit about water cooling in general, you'll be ready to get into the more detailed stuff. Before going out and ordering a bunch of water cooling gear, you'll need to 'spec out' your cooling system. In other words, you'll be determining the specs of the individual components. The Tweaktech link above has some info on determining the necessary water flow and airflow for your water cooling system. Determining the size/shape/type of radiator and radiator fans, the brand of pump, and whether to use an inline pump or reservoir are basically personal choices, and will be influenced by the amount of space in your computer case and your own personal preferences.

After determining the specs of the cooling components, you'll then want to select a coolant. Water is the most common coolant, and is readily available. If you're using mis-matched metals in your cooling system (see my post above), then you'll want to add something to inhibit corrosion (antifreeze works well). You'll also want to add something to prevent funky stuff from growing in your water (antifreeze and bleach both work well). Also, you can check out the Tweaktech liquid coolant comparison to see how some popular coolants stack up.

Now that you've determined the specs of the components and the desired coolant, it's time to visit a few vendors and buy some goodies. So where to by this stuff? I'm glad you asked :) Here are some highly reputable vendors who sell some very good products:

For most people a Danner or Eheim pump is best. Danner pumps are very reasonably priced and of good quality. Eheims are more expensive, but are considered to be the highest quality by many enthusiasts. Rio pumps are used as well, but are considered to be much less reliable for use in computers.

If price is an issue, go with the Danner. They are good pumps and to get equivalent flow from an Eheim will easily cost you twice as much. If you want a nearly silent pump you can put in and never have to touch again go with the Eheim.

Popular models of Eheim are the 1048 and 1250 rated at 158 and 316 GPH respectively. Popular Danner pumps are the Model 2, Model 3, and Model 5, rated for 250, 350, and 500 GPH respectively. Larger pumps are available from both companies, but tend to be less useful due to the large amount of heat they add to the coolant and flow rate limitations in the actual setup.

Eheim pumps are available from DangerDen, while Danner can be bought from PetSmart.

What size you need depends on your setup. Larger pumps are restricted more and more by the size of your tubing while adding more and more heat to the system. An Eheim 1250 pump heats the coolant as much an 866MHz P3 or dual Celeron 300As! Also consider the restrictions in your block and radiator. A maze block, and cooling cube would be better paired with a larger pump then a low restriction setup using an open block and a heatercore.

With that in mind we know that some setups are better with certain pumps then others, but any of the pumps mentioned above will flow enough for a basic watercooling setup.

There is no simple reply. Both are effective ways to cool your coolant.

Heater cores cover a wide range of products, but all of which were originally meant for cars, not PCs. As such they tend to be huge, powerful and cheap. The most well-known is the Big Mama, which is converted for computer use before being shipped. Others are available from your local auto parts or radiator shop for less money, if you don’t mind searching them out and adding the barbs yourself. If cost is important or you need all out performance and you have plenty of room to fit it, then a heater core is probably your best bet.

Most cube radiators are pulled from refrigeration units. Their fins are stacked so they fit nicely into smaller places. Cube radiators perform on par with heater cores in all but the most extreme setups, but tend to restrict water flow more then the low resistance in a heater core. Therefore more powerful pumps are recommended with cubes. If money is somewhat important and you can’t fit a heater core, then a cube is for you.

A third choice is the Black Ice from HWLabs. The Black Ice is custom made for water cooling by a fellow Ars member. It’s very small, easy to mount and packs unbeatable performance for its size. If cost isn’t an issue you probably want a Black Ice.

Have no misconceptions, it is very difficult to mount and fit a heater core in a case. See this thread for what I had to do to fit a core in my midtower.

See this thread for even more info and links:

A bleedline is simply a T-junction with a length of tube that is not connected to anything. This segment of tube is filled with excess coolant then plugged shut. Over time dissolved air floats up into it and more coolant sinks out of it. Eventually this removes the dissolved gases from your coolant, causing your pump to run somewhat quieter and increasing the performance of your coolant. They also provide additional coolant in case of a slow leak. Without one a leaking inline system will quickly cease to cool the processor.

For best results a bleedline should be at the highest point in your system.

First let's be clear that this references the ID (inner diameter of the tubes). Basically the rated flow rate on your pump is impossible to achieve because flow restrictions greatly reduce it. By increasing the diameter of the tubing you can reduce the restriction on your system and therefore come closer to the rated flow rate of your pump.

Now that you know the difference between the two, you should consider if it will help your system. A pump rated for 100GPH isn’t going to improve much, if at all, going from 3/8" to ½". A pump rated above 300 most likely will. Taking this to the extreme, very high flow pumps tend to use 5/8" or even ¾" fittings.

Your cooling system is bottlenecked by its narrowest point. That means the entire system must be ½" ID to have any benefit. So if you want to go ½", then you must get a radiator, waterblock, pump and tubing all with 1/2" ID fittings.

Most pumps are already at least ½" so that won’t be an issue. Likewise DangerDen offers the option of ½" ID barbs on their Maze2 blocks for no additional cost. Radiators can be harder. The Black Ice is not available in ½" as of yet, however nearly all heater cores are 5/8"-3/4" internally and can easily be fitted with ½" barbs. Additionally cubes are now available in ½ inch as well. See “Which is better, a heater core or a cube radiator?” for more info.

Gains from ½" aren’t amazing in most cases, but they don’t require much if any added complexity or cost to your system.

This is an often overlooked question. There are two types of tubing commonly used in watercooling are the silicon tube sold by Danger Den and clear vinyl tubing which can be bought for about 15-25 cents per foot at your local hardware store.

Another consideration is the type of clamp used to seal connections. Silicon is best used with plastic clamps like those sold by Danger Den. Vinyl works well with metal hose clamps (readily available at auto parts stores and hardware stores). The two cannot be interchanged, as I learned the hard way. A metal clamp will cut silicon tube up like Swiss cheese, leaking water when it does so. A plastic clamp will not have enough tension to seal vinyl, leaking water gradually out of your system. Both work fairly well with their own respective tube types, but metal clamps seem better and are easier to fasten.