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As confirmed by independent tests, Indigo Xtreme is the highest performing thermal interface available
High Reliability
- Fully sealed structure - no mess or migration
- Most consistent performance - applies the correct amount of alloy every time
- Gallium-free
- Laser-cut precision
User Friendly
- Fully compatible with copper and aluminum surfaces
- Peel-and-stick application
- Easy clean up - just peel to remove
How It Works
What is Indigo Xtreme™
Indigo Xtreme™ is an Engineered Thermal Interface (ETI) that fits neatly between a CPU lid and heat sink (or waterblock) to keep CPUs cooler. Unlike greases, metallic thermal interface pads or liquid metal alloys, Indigo Xtreme™ is a self-contained and sealed structure, deploying a Phase Change Metallic Alloy (PCMA) which reflows and fills surface asperities on the CPU lid and heat sink. The resultant interfacial layer is void-free and robust, with low thermal contact and bulk resistance.
How Indigo Xtreme™ Works
The overall thermal performance of a thermal interface is the sum of the bulk thermal resistance (which is the inverse of bulk thermal conductance) of the material and its two surface contact resistances (on both the CPU lid and heat sink). Greases have good surface wetting properties and therefore they exhibit low contact resistance; however, they have high bulk thermal resistances. Metallic pads possess low bulk thermal resistances, but surface oxidation limits their surface wetting ability, resulting in higher contact resistance.
Indigo Xtreme™ achieves high thermal performance through the optimized deployment of molten, oxide-free PCMA, thereby yielding low contact resistance and low bulk resistance.
At the heart of the one-of-a-kind Indigo Xtreme™ ETI is a proven PCMA deployment structure. When heated (see Installation Guide), the sealed deployment structure directs flowing PCMA into CPU lid and heat sink micro-surface asperities while flushing out entrapped air. The asperity filling PCMA creates a corrosion-resistant hermetic (airtight) seal between the lid and heat sink, resulting in long-term reliability.
How to Use Indigo Xtreme™
The Indigo Xtreme™ ETI is offered as part of an Engineered Thermal Interface Kit. This kit includes several cleanroom-grade surface cleaning products to ensure the highest quality deployment possible. Once the CPU lid and heat sink surfaces have been prepared, the ETI is aligned to the lid and held in place with its own adhesive layer. Following the bolting of the heat sink to the motherboard, the ETI may be reflowed by simply running the CPU under load as seen in the Installation Guide. 
See http://indigo-xtreme.com/docs/ixheatsinkcompatibilityapplicationnote.pdf for more compatibility info.
How It Compares
Indigo Xtreme™ is a precision engineered Phase Change Metal Alloy (PCMA) for professional, high-end applications pushing the heat flux envelope.
With its excellent surface wetting and high bulk conductivity (as much as 3 times better than the best aluminum and silver-filled greases), Indigo Xtreme™ offers dramatically lower thermal resistance than competing products.
The graph below illustrates increasing CPU wattage and corresponding junction temperature rise with the highest performance thermal interface solutions available today.
The Professional Choice
Indigo Xtreme™ is the professional's choice for the most demanding cooling challenges, and is highly recommended for CPU applications of 150 watts and above. If you operate your CPU at stock wattages and frequencies, Indigo Xtreme™ may not provide significant advantage, and a legacy solution may be adequate for your needs. The extraordinary cooling power of Indigo Xtreme™ is specifically designed for serious overclocking or other challenging applications. With increasing wattage or heat flux, the temperature difference between simple polymeric (grease) solutions and the extra cooling ability of Indigo Xtreme™ increases sharply.
The chart below highlights the performance advantage of Indigo Xtreme™ at only 130 watts of dissipated power with an Intel Core™ i7 CPU. Junction-to-sink temperature rise of Indigo Xtreme™ is almost 4 degrees better than that achieved by Arctic Silver 5.
As dissipated power increases, Indigo Xtreme ™ achieves even greater cooling performance.
ASTM D5470, a standard industry test for quantifying the thermal impedance (resistance) of thermal interface solutions, was used to obtain both thermal contact resistance and bulk thermal resistance values for Indigo Xtreme™ and for the former industry leaders seen in the table and chart below.
| | Indigo Xtreme™ | Shin Etsu X23-7762 | Arctic Silver 5 | Coollabs MetalPad |
| Composition | PCMA composite | Aluminum-filled Polymer | Silver-filled Polymer | Low Melt Alloy |
| Shimmed Bondline Thickness (mils) | ~2 | ~11 | ~11 | ~1 |
| Bulk Resistance | 0.028 | 0.0631 | 0.2301 | 0.015 |
| Contact Resistance | 0.012 | 0.0631 | 0.0791 | 0.305 |
| Overall Resistance | 0.04 | 0.1261 | 0.3091 | 0.320 |
Notes:
1. S. Narumanchi, “Thermal Interface Materials for Power Electronics Applicationsâ€Â, ITherm Proceedings, 2008
2. R. Russo, et al., “Thermal Performance Differences Between ASTM D5470 and “Overclocker†Methodsâ€Â, IMAPS Thermal Advanced Technology Workshop (ATW) Proceedings, 2007
An optimal thermal interface solution possesses both a low contact resistance and a low bulk resistance (the inverse of bulk thermal conductivity). Indigo Xtreme™ achieves high thermal performance through the optimized deployment of molten, oxide-free PCMA, thereby yielding low contact resistance and high bulk conductivity.
Total thermal resistance is the combination of bulk and contact resistances.
Additionally, bulk thermal conductivity was measured (by the cited US government and universary labs above) for the polymeric grease compounds (Shin Etsu X23-7762 and Arctic Silver 5). The Shin Etsu product tested in line with the manufacturer specifications (within measurement accuracy).
Interestingly, the labs measured Arctic Silver 5's bulk thermal conductivity to be 0.941 and 1.12 W/mK, figures which are far lower than the manufacturer's claim of >8 W/mk (>350,000W/m2 °C at 0.001 inch layer).
The increased contact resistance of Coollab's MetalPad may be due to inadequate pad thickness to accommodate a 1 mil BLT and surface asperities of the test blocks.
The best performance:
Indigo Xtreme™ is the clear winner over all alternatives for a high-performance thermal interface solution.
Indigo Xtreme™ Installation Guide (PDF) for the Intel Core™ i7 Processor
Using Socket 1366
