Gigabyte Geforce 6600 GT Silent-Pipe II GV-NX66T256DE

Written by John Chen    Thursday, 08 December 2005 11:00
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Gigabyte Geforce 6600 GT Silent-Pipe II GV-NX66T256DE
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Gigabyte is no stranger when it comes to releasing the latest enthusiast hardware.  The well known and respected company has taken things a step further and started developing innovative features to accompany their latest products.  The previously reviewed Radeon X800XL came equipped with a large passive heatpipe heatsink to allow enthusiasts compute and game with utter silence.  Perhaps the only downside to a passively cooled video card is the overclocking headroom.  Without an active fan to help dissipate the heat, high end video cards can become toasty in a matter of minutes.  Thankfully, the X800XL is built on the smaller 0.11 micron die with lower heat output.  This allowed the Gigabyte Radeon X800XL to overclock rather decently. 

Gigabyte is back again with another innovative release.  This time around is a new silent heatpipe heatsink for the mid-ranged video card, the Nvidia Geforce 6600 GT. 



Gigabyte Geforce 6600 GT Silent-Pipe II

The Geforce 6600 GT is still currently a very popular choice for a mid-ranged video card.  The price of a 6600 GT video card is well within the budget of any gamer and the performance behind the GPU is nothing to complain about.  Since there is a large majority of gamers who own a Geforce 6600 GT, I find it disappointing to see that there were no games included in the Gigabyte bundle.  Gigabyte typically includes a game or two with their video cards, but this Silent-Pipe II 6600 GT seems to have missed out on that.  The Silent-Pipe II 6600 GT comes with HDTV support and is evidenced by small video-out box.  The box allows use of standard S-Video and component video cables.  The Silent-Pipe II 6600 GT comes with a single DVI and a single analog output for your display.  There is a single DVI-to-analog adapter included for those who wish to run a dual display setup.

The whole point of Gigabyte's new 6600 GT is the utilized heatsink.  The entire heatpipe heatsink design is comprised of three pieces--the base that makes contact with the GPU, the multiple fins at the at the back side of the video card, and the multiple fins at the front of the video card.  There are only two heatpipes used for this heatpipe design, with each heatpipe stretching to its own stretch of multiple fins.  The thermal interface used between the copper base and the GPU is a layer of yellow thermal pad.  I still do not understand why Gigabyte continues to use these yellow thermal pads when a thin layer of thermal grease provides much better results.  The Silent-Pipe II is aimed to provide great thermal performance at a silent level, so why hinder the cooling performance with a cheap layer of thermal pad?

As you can see from the image below, the sticky yellow thermal pad left residue on the 6600 GT core.  I attempted to use some Goo Gone and rubbing alcohol to rid the residue, but neither helped.  Most 6600 GT video cards are equipped with 128MB graphic video, but the Silent-Pipe II comes with a whopping 256MB of DDR2.  The video memory is powered by Infineon's 2.5ns memory ICs and is left bare with no heatsinks and no cooling aid.  Theoretically, these 2.5ns chips operate at 400MHz, which in turn means that it will run at DDR2 800MHz.  The memory speed of the Silent-Pipe II 6600 GT is defaulted to DDR2 800MHz, which means that the memory is already running at the maximum theoretical speed.  Let's cross our fingers and hope that there is some headroom left.



Geforce 6600 GT GPU

  PowerColor Radeon X800 GT Gigabyte Silent-Pipe II Geforce 6600 GT
GPU Core Clock 475 MHz 500MHz
Memory Clock 2 x 490MHz 2 x 400MHz
Pixel Pipelines 8 8
Memory Bus Width 256 bit 128 bit
Memory Size 256MB DDR3 256MB DDR2

The price point of the Silent-Pipe II fiercely competes with ATI's new mid-range X800 GT line.  The Gigabyte Silent-Pipe II Geforce 6600 GT comes clocked at 500MHz for the core and 400MHz for the memory, or DDR2 800MHz.  The 6600 GT comes with 8 pixel pipelines, which is commonly found in mid-ranged video cards.



Test Setup and Overclocking


Overclocking Nvidia video cards is a very easy task.  Simply go to Google and search for "coolbits".  Coolbits is a registry hack that opens up the overclocking option within Nvidia drivers.  It displays the core and memory frequencies and allows automatic or manual overclocking options.  With no cooling fans blowing at the Silent-Pipe II 6600 GT, the automatic overclocking feature pushed the card to a nice 518MHz for the core and 841MHz for the memory.  The headroom for the core did not seem all that much, but since it is passively cooled, the result is understandable.  The memory headroom was the surprising part; it was able to run 41MHz past the theoretical limit.  After spending some time manually overclocking the video card and testing for artifacts via 3DMark03 and 3DMark05, I settled at a very nice result of 590MHz/855MHz.  The GPU sure had more power!  Remember, this is all passively cooled. 

Testing Setup and Methods:

  • AMD Athlon 64 3000+ (9 x 310HTT = 2.79GHz)
  • DFI NF4 SLI Infinity
  • 2 x 1GB OCZ Platinum PC4000 EB (310HTT w/ 166 divider = ~254MHz 2.5-3-2-6)
  • SilverStone ST60F
  • Cooler Master Hyper 6+
  • Windows XP Pro w/ SP2 and DirectX 9.0c
  • Nvidia nForce4 AMD 6.70
  • Nvidia ForceWare 81.85
  • ATI Catalyst 5.10


  • Chronicles of Riddick: Escape from Butcher Bay (OpenGL)
  • Doom 3 (OpenGL)
  • Far Cry (DirectX)
  • Unreal Tournament 2004 (DirectX)
  • Quake 3 (OpenGL)
  • 3DMark03 (DirectX)
  • 3DMark05 (DirectX)

Video Cards Tested:

  • ATI Radeon X800XT
  • ATI Radeon X800XL
  • PowerColor Radeon X800 GT
  • Gigabyte Silent-Pipe II Geforce 6600 GT


Chronicles of Riddick: Escape from Butcher Bay

Chronicles of Riddick: Escape from Butcher Bay is one of the most system intensive games I have ever encountered.  It is graphically beautiful and very taxing on the video card.  The game uses the latest OpenGL and is a great benchmark to test the video card's OpenGL performance.  The results show that the Silent-Pipe II 6600 GT takes a slight lead on the ATI's X800 GT counterpart.  This is due to the fact that Nvidia has always had better OpenGL support.



Doom 3

Doom 3 is another very video intensive game that provides incredible graphics of game surroundings and details.  The game is considered to be one of the best benchmarks to test for your system's gaming potential.  Just like Chronicles of Riddick: Escape from Butcher Bay, Doom 3 utilizes OpenGL.  The results are very similar to the Chronicles of Riddick: Escape from Butcher Bay. 



Far Cry

Although the replay value is not high, due to lackluster online multiplayer options, Far Cry still serves as one of the most popular games around.  I still remember Far Cry as the first most video intensive game I have ever laid eyes on.  The game shocked me when I found out my high end gaming machine could not handle it with full details turned on.  Far Cry is based off DirectX and is a great benchmark to test for the video card's DirectX capabilities.  This is where the 6600 GT started to fall behind, and quite badly.  ATI's dominance with DirectX based games is something Nvidia has yet to conquer.  The 6600 GT does gain quite a bit of improvement after some overclocking.



Unreal Tournament 2004

Unreal Tournament 2004 is one of the most popular online first person shooters around.  The game is indeed addicting and takes a lot of skill to master--gameplay is so fast that it takes practice to master your aim.  Much like Far Cry, the game is also based off of DirectX.  Again, we see that the 6600 GT is no match for the ATI counterpart.  Overclocking did help performance, but not enough to allow full details at the highest resolution.



Quake 3

Many of you might wonder why I would throw in this benchmark since the game is ridiculously old.  The reason is that it is a great benchmark to test a video card's old OpenGL support and performance.  While not very system intensive (runs at 500 frames per second for Pete's sake), the game is still currently popular and widely played.  I found the Quake 3 benchmark to be quite mind boggling.  As mentioned earlier, Nvidia provides better OpenGL support so I expected the 6600 GT to dominate the X800 GT.  Surprisingly, it was the other way around.



Synthetic Benchmarks

3DMark2001SE used to be a great graphical benchmark until people started to realize that it is also very system dependent, meaning that tweaking memory timings and speeds greatly affects performance.  3DMark03 was released and became one of the most referred to benchmark for graphical power.  It is based off of DirectX 9 and since ATI dominates the DirectX performance, ATI usually tends to win in this area.  3DMark05 is also very similar to 3DMark03, but just a new version with more stringent testing methods.


Conclusion and Thoughts

From the performance standpoint, Nvidia seems to have lost their long held crown in the mid-range section of video cards.  Nvidia's Geforce 6600 GT does not seem like it can keep its grasp of the mid-range section anymore.  The performance is slipping to ATI and it is only a matter of time when Nvidia fights back. 

The focus of the Silent-Pipe II 6600 GT is not the performance of the video card, but rather the innovative cooling technology developed by Gigabyte.  The Geforce 6600 GT is one of the most popular cards currently on the market.  The reason is that it provides gamers the performance they need to play their latest games and it provides HTPC enthusiasts all the technology, like native HDTV support, they need to get a good theatre system going.  Gigabyte's approach with the Silent-Pipe II seems to aim at HTPC enthusiasts.  The most obvious reason behind that is the lack of games in the package bundle.  The other is the silent cooling.  Perhaps the hardest goal to achieve when building a good HTPC system is reducing noise to a minimum.  With a passive heatsink, zero noise is generated.  That is one less thing HTPC enthusiasts have to worry about.  Who wants to hear their fans hum when watching a movie?  That is not very enjoyable.  Pairing a passive heatsink with the 6600 GT is a great idea.  Do not be fooled by the heatpipe heatsink, though.  It still allows the video card to be overclocked quite highly.  Enthusiasts who care less about noise and more about performance should look elsewhere.  They will find better performance through ATI's X800 GT line. 


  • Passive cooling = zero noise
  • Highly overclockable
  • Heatpipe design keeps the card running cool
  • Ideal for HTPC systems
  • Affordable


  • Destroyed by ATI's mid-range counterpart
  • No games in bundle

We would like to thank Gigabyte for providing us the sample.  If you have any questions or comments, feel free to hit us up in the forums. You can also check out more of our latest reviews on the front page.