Reviewed by Barry Little - June 11, 2008

Manufacturer: Noctua

Part Number: NT-H1

Price: $8.99 at Amazon.com

No one can argue the importance of a quality CPU cooler. Especially if you’re an enthusiast trying to wring every last bit of power out of your processor via overclocking, while keeping increased heat under control. Equally important, is the use of a quality thermal compound between the cooler and the processor heat spreader. That’s why Noctua's NT-H1 Thermal Paste is the subject of today’s review.

About Noctua

What Does Noctua Mean?

The little owl, Athene noctua, is the symbol of the Greek goddess Athene, who represents wisdom, science and strategy. She has a marked preference for the most clever among the Greek heroes, like Odysseus, who endure their adventures by the use of savvy consideration instead of mere force. Until today, the owl symbolises intelligence and prudence, its manlike face emblematises attentiveness and communication. We from Noctua follow the suit of its calm and accurate observation in the dark, its soundless flight as well as the effective, economical use of its powers and precise attack.

Noctua aims at establishing a new level of quality and performance "Designed in Austria" through paying attention to the users' needs in a market burdened with all kinds of frills and furbelows and providing sound-optimised premium components, which serve their purpose in a smart, precise and reliable manner.

Noctua arises from a cooperation between the Austrian Rascom Computerdistribution Ges.m.b.H and the Taiwanese Kolink International Corporation and entertains a development partnership with the Austrian Institute of Heat Transmission and Fan Technology (Österreichisches Institut für Wärmeübertragung und Ventilatorentechnik, ÖIWV). These connections form the key to the achievement of our goal: The partnership with the ÖIWV permits the application of scientific measurement instrumentation, methods of calculation and simulation technology in the R&D process. Rascom's long, customer-oriented experience in developing and distributing sound-optimised high-end products ensures a clear focus on the users' needs. The use of Kolink's advanced manufacturing technology and ultra-modern production plants allows us to efficiently implement our technical edge and provide solutions of the highest standard in quality and performance.

All Thermal Compounds Are NOT The Same…

There are two popular myths about thermal compounds—also known as thermal paste, thermal grease or the more “technical” TIM (Thermal Interface Material):

“Don’t listen to those ‘techno-dorks’—all thermal paste is alike—save your dough and get the cheap stuff!” 

“Don’t worry about slapping lots of paste on the processor—the more the better!”

I cringe whenever I hear comments like that.

Thermal compounds are necessary for the same reason that gaskets on your car’s engine are necessary—to create a perfect bond between two imperfectly machined surfaces. In the instance of your car, it’s to keep fluids in. On a computer, it’s to initiate proper heat transfer. No matter how mirror-smooth you machine a piece of metal—whether it’s the cylinder head on an engine or the base of a CPU cooler’s heatsink, the surface will always have microscopic imperfections. These imperfections allow fluids to escape (your car), or creates “hot spots” that prevent the proper transfer of heat from one surface to the next (your computer). And in both examples, that’s definitely bad news.

Just as there are different grade motor oils for cars, there are different types of thermal compound. The materials used in them vary in quality and consistency. Some thermal pastes require a “break-in” period before they become fully effective. The manufacturing process and the quality and mixture of materials within the thermal compound not only determines how effective it is in transferring heat, but its longevity under actual use.

Some thermal pastes that claim to be “just as good as (insert name-brand thermal compound here)—only cheaper,” may actually use a lower-grade or lower ratio of silver per gram. Or they may simply look gray or silver in color while not having any silver within the compound at all. Needless to say, when corners are cut to shave manufacturing costs and turn a better profit on thermal compound, you can expect its heat transfer capabilities to be compromised.

“More is better” is not an unusual philosophy among enthusiasts, whether it’s more cores per processor, multiple video cards in an SLI or Cross Fire config or higher overclocks. Just as you’re likely to hit a point of “diminishing returns” with some games that simply won’t scale to take advantage of a quad SLI or Cross Fire set-up, you can also go overboard with thermal paste. While different pastes require different application techniques, the one constant is that applying too much hinders heat transfer between the CPU and heatsink just as much as not apply enough. You should always follow the manufacturer’s instructions on applying your particular thermal compound to-the-letter. Of course, some manufacturer’s instructions aren’t always as clear as they should be. In which case, it’s best to err on the conservative side than having thermal paste oozing out from around the edges of the processor and heatsink like a peanut butter and jelly sandwich.

The Noctua NT-H1 Advantage

Whether you’re looking for an aftermarket thermal paste to aid in your overclocking endeavors or you simply want a cooler-running CPU, choosing one can be difficult with all the different products out there claiming to be better and cheaper than their competitors. Here are some things you should look for when shopping for thermal paste:

Single or multi-purpose—some compounds are formulated for optimal use with CPU coolers and water blocks. Some will also work safely on coolers and water blocks as well as regular chips that are directly cooled by heatsinks. So if your goal is lower CPU temperatures, silver and other metal-based compounds are a good choice to use between the metal CPU heat spreader and the cooler heatsink base or water block. Video card GPUs and memory chips along with motherboard North and South bridge chipsets and MOSFETS are notorious for running hot. The situation only gets worse when you start overclocking. Temperatures for these components increase exponentially when you start cranking up clock and bus speeds, and bumping up voltages to stabilize things. Many video card GPUs run hotter than the maximum safe limit for the fastest quad-core processors. It’s not uncommon to find excessive thermal paste or worse—thermal tape—applied on these components. Whether you’re installing an aftermarket video card cooler or trying to enhance the existing cooling to give yourself more overclocking headroom and lower system temperatures, a ceramic thermal compound works best here.

 

Conductivity—the ability of a compound to be electrically conductive. As such, if the compound comes in contact with electrical traces, pins and leads, it can cause some nasty shorts that can damage motherboards, processors and expansion cards. You always want a non-conductive thermal compound. If it doesn’t say non-conductive on the packaging, assume that the compound is conductive and be extra careful when applying it. By the same token, just because thermal paste is non-conductive doesn’t mean it’s OK to get it all over everything. Why? Even non-conductive compounds can be slightly capacitive—enough to cause you some grief if any excess manages to bridge two electrical paths (traces) on a circuit board that run close together.

 

Application and Removal—how easy it is to apply and remove the thermal paste should also be taken into consideration. Some thermal compounds need to be brushed on, others require a single dab. Some practically “stick” the base of the CPU cooler to the CPU’s heat spreader making it difficult to remove when cold. The system has to be run for a short period of time to heat up and “loosen” the bond—a common occurrence among cheaper, off-brand compounds. Some compounds require more effort to clean off the surface of the heat spreader and heat sink than others.

 

Burn-In and Longevity—some compounds require a break-in period before optimal heat transfer is achieved (the length of time varies). Some are only formulated to be used in a test environment where frequent heatsink and processor swapping and qualifying are the norm, rather than long-term use.

With that in mind, let’s take a look at what Noctua brings to the thermal compound table with their NT-H1.

Pretty impressive features, but nothing unexpected or surprising when you consider all the worldwide awards and accolades won by Noctua for their line of ultra-quiet fans and hi-performance CPU coolers.

Package and Product

Noctua’s brown and blue boxes with their owl corporate logo have become quite a familiar trademark in the enthusiast community where silence is as equally valued as maximum cooling performance. So it is with the user-friendly blister pack that the NT-H1 comes in. User friendly because all it takes to open it, is spreading the blister pack’s tabs along the back and popping out the cardboard insert, where the tube of NT-H1 can be freed from its form-fitting compartment. Certainly better than to having to hack your way through a vacuum-sealed blister pack with a knife or scissors that never really seem sharp enough.

Noctua’s NT-H1 Thermal Paste comes in a 1.4ml syringe tube—enough for 15 applications. You won’t need to go hunting for a large paper clip or some other long, skinny and sharp instrument to unseal the tube to squeeze out the paste. The cap is on securely enough to insure that none of the product leaks out. The tip of the tube is shaped so that it’s easy to squeeze out just the right amount on top of your processor’s heat spreader.

The main selling points of NT-H1 are outlined on the front of the insert with their familiar bullet-point icons. Flip it over for the installation instructions, actual specifications and NT-H1, the marketing 411 on the thermal paste in six different languages, and the usual for-your-safety caveats about using any thermal compound.

As always, Noctua’s packaging provides clear and to-the-point information on the product, making it easy to determine what you’re plunking your hard-earned dollars for, while being confident in doing so.

Installation

A thermal paste is only as good as the cleanliness of the surface it’s applied to. Any previously applied thermal pad or compound must be completely removed from the CPU heat spreader and the base of the cooler’s heatsink. I’ll never forget the almost cavalier attitude of some on-site techs at my former place of employment, who didn’t hesitate to slap on fresh thermal paste like ketchup on a burger on top of the caked remains of the original thermal pad when replacing motherboards. It was always those same techs who grumbled when having to return usually less than a week afterward to replace an overheated CPU…

For thoroughly cleaning and prepping the CPU heat spreader and base of the cooler for a fresh application of thermal paste, it’s hard to beat Arctic Silver’s ArctiClean, and it’s what I rely on exclusively. If you don’t have any handy, some good old-fashioned 91% Isopropyl Alcohol will get the job done with a little more effort required. Because any contaminants—lint, dust or oil from your fingertips—can reduce the effectiveness of the thermal paste, it’s also important to avoid touching the surface of the spreader and heatsink. Also, be sure to use a lint-free cloth with your chosen cleaning solution. Believe it or not, coffee filters work great for this purpose (besides help keeping the caffeine flowing during those all-nighter rig-building and benchmarking sessions). Don’t forget a can of compressed air to blow away any stray dust that might end up on the heat spreader before you apply the compound and install the CPU cooler.

Once the heat spreader and heatsink surfaces are prepped, apply a single 4 to 5mm drop—a bead, actually—of Noctua NT-H1 to the center of the CPU heat spreader. Be sure to heed Noctua’s warnings in the instructions on back of the package insert. Applying too much NT-H1 can hinder proper heat transfer between the CPU and cooler by acting as insulation rather than a conductor, causing higher CPU temperatures instead of the other way around.

Lower the CPU cooler in place and twist it slightly from side to side to help spread the NT-H1. Secure the CPU cooler and connect the fan. Boot the system and go straight into the CMOS (BIOS) and check the CPU temperature and fan speed. Your CPU should be either lower or at its normal idling temperature, which will vary depending on your particular CPU and cooler installed. Minor temperature spikes of a few degrees are normal. You should not see your CPU temperature climb to at-load temperatures. If you do, shut down your system immediately and check the following:

Installing NT-H1 was as uneventful as any other thermal paste I’ve used. Chances are you aren’t reading this as just another “how-to-apply-thermal-paste” tutorial (if you are, OK by me). You probably want to see how it performs against other thermal pastes.

So let’s get to it.

Testing

Here’s the test bed I’ll be using:

Going up against Noctua’s NT-H1 Thermal Paste are the following:

Arctic Silver 5—consisting of high density 99.9% pure micronized silver and ceramic particles, and optimized for use between hi-performance CPUs, heatsinks and water-cooling blocks, Arctic Silver 5 is one of the most widely recognized and used non-conductive silver thermal compounds in the world. As such, it is consider a standard that all other thermal compounds are measured against. Arctic Silver 5 has a “break-in” period of up to 200 hours—about 8 ½ days (longer on a system without a fan on the heatsink or a low-speed fan), before it reaches maximum thermal conductivity.

 

Arctic Silver Céramique—a combination of aluminum oxide, boron nitride and zinc oxide particles makes up this premium, non-conductive ceramic thermal compound that out-performs lesser metal-based compounds, making it suitable not only for CPU heatsinks and water blocks, but heatsinks used on motherboard chipsets, video card RAM and GPUs. Céramique takes a minimum of 25 hours (longer on a system without a fan on the heatsink or a low-speed fan), before it reaches maximum thermal conductivity.

 

ASUS Cooler—ASUS bundles it in a small syringe tube with their line of CPU coolers. I included it for comparison as a representation of thermal paste products that are usually bundled with coolers by companies that typically do not market thermal paste as a separate product. No specs are available on the compound, though my past experience with it indicates that it probably one of the better quality “generic” gray thermal pastes that comes with a CPU cooler.

 

Zalman ZM-STG1—bundled with their top-of-the-line CPU coolers, Zalman ZM-STG1 is also available as a stand-alone product in a small 3.5g bottle with a built-in applicator brush. While Zalman does not publish which materials are used in ZM-STG1, the gray-colored non curing compound has a consistency that’s slightly thicker than nail polish with a Temperature Stability range of -40°C-150°C (-40℉-302℉), and a Thermal Conductivity rating of 4W/mK. It takes 7 days of normal computer use (including power cycling) for ZM-STG1 to reach optimal thermal conductivity.

EVEREST Ultimate Edition was used to record CPU idle temperatures for a cold start, then running at the desktop for one hour. Under load tests were conducted using the Stress CPU, Stress FPU and Stress Cache modules of EVEREST’s System Stability Test to give both cores of the overclocked E6600 Core 2 Duo Processor a good workout and ramp up the processor heat—both figuratively and literally, for one hour. EVEREST’s logging feature was used to record minimum, maximum and average temperatures during the idle and load test sessions.

Click to Enlarge

Each thermal paste product was applied as per the manufacturer’s specific instructions, with the CPU spreader and heatsink base of the Zalman CNPS9700 NT CPU Cooler thoroughly cleaned before each thermal compound product was applied for evaluation. Click the following links to view the instructions for each thermal paste product:

Noctua NT-H1

Arctic Silver 5

Arctic Silver Céramique

Zalman ZM-STG1

The ASUS Cooler Thermal Paste provides the same, generic black and white drawing of the syringe tube over the CPU with “Apply the thermal grease to the CPU” as the only written instructions, for all their CPU coolers. Nothing on whether to use a small bead of compound or apply the entire tube—a practice that was once common with older Intel Pentium 4 processors. Well, that was then and this was now, so I applied the same size bead of ASUS paste as I did with the NT-H1 with no detrimental effects.

All manufacturers’ recommended break-in times where applicable, were observed so that the product could obtain the best possible thermal conductivity. Otherwise the thermal benchmarks were conducted right after the thermal paste was installed. Room temperature was at 68° C for all tests (not an easy feat this time of year on the East Coast).

I choose to use the Zalman CNPS9700 NT rather than the recently reviewed Noctua NH-U12P CPU Cooler, because thermal pastes should not be considered “brand-specific” when it comes to working with CPU coolers. A quality thermal paste should provide improved thermal transfer characteristics regardless of the manufacturer of the CPU cooler.

The results I achieved reflect the specific hardware and testing environment that I used. Your results will vary based on the same criteria. Your processor, the design of your CPU cooler and the number and configuration of the heat pipes it has; whether or not you’re overclocking and how much, the airflow characteristics of your case and hardware installed, and the air temperature in the room will directly impact your cooling performance.

The results speak for themselves. We have a new champion in CPU cooling—Noctua’s NT-H1 Thermal Paste!

Final Impressions and Conclusion

Having the best CPU cooler that money can buy won’t do you much good without a quality thermal paste to back it up. Just as they’ve done with quiet hi-performance fans and coolers, Noctua definitely delivers with their NT-H1—a paste that can not only keep up with but out-perform the best of them in terms of ease and convenience of use and thermal conductivity.

Let’s face it. In this age of more processor cores and faster GPUs, whether it’s 25 hours or eight days, who really wants to wait for their thermal compound to “break in” to get the most benefit from it? With Noctua NT-H1, you are good to go as soon as you apply it—period. Some thermal pastes can lose their effectiveness sooner than you’d expect, particularly on highly overclocked systems—usually requiring that you re-apply them at least once a year to maintain their effectiveness. Noctua guarantees the effectiveness of NT-H1 when applied properly to your CPU for up to three years. NT-H1 can also be used on high-end cooling systems like the CoolIT.

Clean up is effortless with ArctiClean, though that’s hardly a surprise. There are few thermal pastes on the market—including the notoriously tough Intel and AMD thermal pads—that ArctiClean can’t handle. My bottle of 91% Isopropyl Alcohol has been collecting dust for the last four years ever since I’ve been using ArctiClean. For those of you who were wondering (and to satisfy my own personal curiosity), I dusted off the bottle, and ran a second set of tests to see just how well it would fare cleaning up the suite of thermal pastes used in this review. Wasn’t much of a surprise that Noctua’s NT-H1 Thermal Paste was still the quickest and easiest to clean from the heat spreader and heatsink with the alcohol, followed by Arctic Silver 5, Zalman ZM-STG1, Arctic Silver Céramique and ASUS Cooler.

Easy set-up and clean up, great thermal properties and no break-in period—is there anything that Noctua’s NT-H1 Thermal Paste can’t do?

Well, like Arctic Silver 5, you probably shouldn’t try to use it as a replacement for thermal paste or tape used between motherboard chipsets and heatsinks, or video card RAM sinks and GPU coolers. NT-H1 won’t make a cheap, poorly designed CPU cooler perform like a good one. Nor will it make a top-of-the-line cooler perform to its full potential that is improperly installed, or hampered by a case full of dust-clogged fans, and messy cabling. The results you achieve with your cooling solution is only as good as the weakest link in that solution.

There’s no end to the selection of CPU compounds available out there. You could just as easily pick any of them for the job instead of Noctua’s NT-H1 Thermal Paste. But with an on the street price of nine bucks or less, no break-in period, excellent thermal conductivity, performance and long-term stability, you have to ask yourself a question; why would you?

Final Score: