Noctua NT-H1 Thermal Paste Page: 1
All modern PC CPUs produce enough heat that they need a heat sink. Almost all of them need a heat sink with a fan. Many heat sinks come with some sort of thermal transfer paste pre-applied - typically a patch of grease; thermal paste; goop or whatever you want to call it.

With the heat output of modern CPU's, and even more imortantly, overclocked CPU's, there just has to be something between CPU and heat sink. The reason why there has to be something there is that the two mating surfaces of processor and sink aren't flat. They may look flat...They may have a mirror polish. But, on a microscopic scale, they are vastly different.

Without thermal transfer compound, everywhere heat sink metal doesn't mate with CPU package material is a teeny-tiny air gap. Air is a good thermal insulator. As long as your heat sink looks flat when you lay a ruler on it then there'll be a decent amount of actual contact, of course, but the amount of heat that'll actually make it around the air gaps may be surprisingly small. Hence, thermal compound. It's grease with lots of minuscule thermally conductive particles mixed into it, basically. It doesn't conduct heat as well as direct contact, but it's a heck of a lot better than air gaps.

Now here is where the picture becomes a little grey, and perhaps a little confusing for the uninitiated. Not all thermal pastes are created equal! Many people tend to purchase a thermal paste that the majority says is better, quite often without considering viable alternatives that exist out there. It's understandable, it is the nature of the consumer. Take Arctic Silver and their AS5 thermal paste for example. Sure it's a proven performer, but there are better performing pastes out there, and quite often cheaper than AS5.
Noctua NH-1

Today I have been given the opportunity to test Noctua's NT-H1 thermal grease which has been stated as a pro-grade TIM solution for enthusiasts who demand both exceptional performance and maximum ease of use. Here's what Noctua have to say about their product:
...A hybrid compound of different micro-particles that allows for minimum thermal resistance, excellent ease of use and outstanding long-term stability.
Let's take a brief look at the specifications for Noctua's NT-H1...
Volume: 1.4ml (for at least 15 applications)
Specific Gravity: 2,49 g/cm³
Colour: grey
Recommended storage time (before use): up to 2 years
Recommended usage time (on the CPU): up to 3 years
Peak operating temperature: -50°C to +110°C
Recommended operating temperature:  -40°C to +90°C
Noctua's NT-H1 on paper looks every bit of what we'd expect from the Austrian based cooling company. There are some additional features of NT-H1 that you may find interesting, but that I can't include here due to space constraints. The additional details can be found here.

Noctua NT-H1 Thermal Paste Page: 2
Noctua's NT-H1 comes professionally and thoughtfully packaged, just as we'd expect it to. The packaging provides a plethora of technical information and details on the rear and the front shows off the tube of thermal paste well in the typical brown and blue Noctua theme.
NH-1 package front NH-1 package rear
I'm not going to go into any detail about the syringe of Noctua NT-H1 simply because it is only thermal grease afterall. I don't want you falling asleep on only the second page of the review. Let's have a little bit of a closer look at the Noctua NT-H1 thermal paste...
A Closer Look
While most typical thermal greases use silicon grease as a base medium, the new breed of thermal greases like Noctua's NT-H1 and Tuniq's TX-2 can be significantly different. I have decided to use 3 other thermal greases that I had kicking around at home to reinforce this further. Pictured below are: Noctua's NT-H1; Thermalright grease; Arctic Silver 5, and XSPC's thermal grease.
Thermal paste specimens Thermal paste test specimens with goop
Ceramic based thermal greases which can usually be identified by their white appearance tend to be very easy to spread, but over time can tend to leech a 'watery' type of fluid if left on the shelf. Metal-based thermal greases like AS5 and the XSPC thermal grease contain metal particles (usually silver), and can be a little viscous which may make application a little tricky when trying to get a consistent spread of grease. In my experience, metal-based greases can tend to dry out a little over time when left on the shelf. I'm not 100% sure what the makeup of Noctua's NT-H1 is but it's probably the easiest to handle and apply straight out of the tube of the 4 syringes shown above. 
Water leaching test
In a little test I placed 4 small dobs of the thermal grease on a sheet of A4 copy paper and left them in the open air over night. In the image above you can see the end result. Both the Thermalright (second from left) and XSPC (far right) suffered from a major loss of their binding agent. They had also dried out quite significantly as a result. The Noctua NT-H1 ( far left) and AS5 (second in from right) on the other hand managed to keep the loss to a minimum. If you look closely, the NT-H1 actually experiences the least amount of loss when compared to AS5. One could hypothesise that this may be an indicator of some sort as to how the thermal pastes would perform over time, and that the Noctua NT-H1 may be the most stable and consistent thermal grease of those tested.
Anyway, let's see how we're going to test the heat transfer properties of each grease on the next page...

Noctua NT-H1 Thermal Paste Page: 3
For the testing phase of this review I will be assessing the heat transfer properties of each thermal grease by applying it in the system below:
Intel Q6600 G0 Stepping Quad-core (@ 2.4Ghz) with Intel reference heatsink
ASUS P5B Deluxe wifi/App Motherboard
OCZ FlexXLC PC2-6400 RAM
Each thermal grease specimen will be applied in 3 seperate instances and the hardware thoroughly cleaned between application with ArctiClean. Idle and load temperatures of the processor will be measured using Core Temp 0.98.1. Load temperatures will be simulated by running 2 x instances of SP2004 ORTHOS Edition. Idle temperatures were recorded only after they had settled and load temperatures were recorded after 20 mins of SP2004. An average was taken of the three runs per  thermal grease application. Ambient temperatures at the time of testing was between 23.4 and 23.6 degrees Celcius.
Test Results
 Idle temperature chart
Load temperature chart
Result Observations
From the results above we can see that Noctua's NT-H1 provides consistently better heat transfer at idle and load temperatures than AS5. Sure AS5 requires around 200 hours to cure properly and temperatures will drop steadily during that time, but NH-1 manages to do it straight out of the syringe. I'm sure that Noctua's NT-H1 will see some temperature reduction given a longer curing time also. The Thermalright grease was the standout performer though during the testing, and subsequently, deserves some credit.

Noctua NT-H1 Thermal Paste Page: 4
I must admit that I was really impressed by the Noctua NT-H1's performance today. NT-H1 was very easy to apply; demonstrated a better stability than the other greases and provides very satisfactory results straight out of the syringe. If you're looking to get yourself some Noctua NT-H1 thermal grease then your best bet is to head to Aqua-PC's where you can pick some up for around a fiver (inc VAT).
After speaking with the Press Manager from Noctua, I have been informed that there is now a revised version of NT-H1 available. The newer version has been available since late January and promises an improved formula which spreads even easier than this one. Should you purchase some Noctua NT-H1 after reading this review you can rest assured that it will be the newer revision. Subsequently, Noctua are sending me out the new version of NT-H1 and as soon as I have run the tests I will include an addendum to this review.
The Good
* Easy to apply
* Good performance right out of the syringe
* Long-term stability
 The Mediocre
* Slightly dearer than AS5
The Bad
* Nothing to report
OC3D Recommended award
Overclock3D would like to thank Noctua for supplying todays review sample
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