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January 3, 2003 by Brett Wasserman
- Postscript added Jan 5/03
Brett Wasserman is a PC engineer with over 20 years experience in the industry who recently became interested in writing after seeing the dearth of technically informed reviews on the electronic gear that goes into PCs. His recent reviews at Overclockers.com rank with the most thorough and insightful motherboard analyses published in the realm of popular PC tech web sites. Here, Brett contributes his first article for SPCR, a review about a product of much recent discussion in our Forums.
As many of you already know, the Korean company Zalman has been marketing an ever-growing line of rather unique products aimed at keeping your PC components as quiet as possible while still maintaining an acceptable level of cooling. The engineers and management at Zalman have carved out a very specific niche for themselves in the balance between noise and cooling performance. Their products are not designed or marketed as being appropriate for overclockers, but rather for those people who are seeking to reduce the amount of noise that stock cooling solutions produce.
Today we're going to have a look at the Zalman ZM80 VGA card cooling solution. The past few generations of 3D video cards have become quite a bit more complex and power hungry than earlier ones. This has prompted both Nvidia and ATI to include small but powerful fans, in addition to heat sinks, in their reference designs. The fans chosen for video card cooling are usually small, fast and rather loud. They do, however, perform quite well in keeping video cards at fairly low temperatures. But what can one do if the noise they produce is just too much for the environment? Well, what about eliminating the fan and dramatically increasing the size of the heat sink?
That's just Zalman has chosen to do. The Zalman ZM80 is a very large aluminum heat sink assembly with a heat pipe that is designed to shuttle heat away from the GPU core. As you can see in the picture below,
the ZM80 is designed to be installed on both sides of your video card, with the heat pipe (right) under the large outer heat sinks.
The ZM80 is comprised of five major components:
1) Front Side heat sink base
2) Back Side heat sink base
Zalman includes 2 different sets of anodized aluminum heat sink bases in the ZM80 package. The left hand set in the picture (the "A" set in Zalman's documentation) is designed to be used on Nvidia GeForce4 Ti cards and other cards with existing heat sink mounting holes that are far apart. The "B" pair is intended to be used with cards where the holes are much closer together. Zalman provides very little guidance (outside of the above) in their manual about which pair of bases to use.
Each of the base components has a lengthwise, rounded groove that the heat pipe sits in.
3) Heat pipe
The heat pipe is a copper pipe, gold plated and sealed at both ends. Zalman makes no mention of the pipe's contents but for it to function a substance that can undergo a liquid to gas (and back) phase change must be able to occur at the temperatures that the pipe is exposed to.
Briefly, a heat pipe design allows thermal transfer by absorption of heat on one side of the heat pipe through the boiling of the internal LIQUID substance. The heat is removed on the other side of the pipe, by condensing the gas formed by boiling back into a liquid. The process is continuously repeated (assuming the temperature on the 'cold' side of the pipe is sufficiently colder than that of the hot side.) If the overall environment doesn't have a sufficiently large temperature difference -- either because it's too cold, or too hot, the heat pipe cannot function.
4) Front Side heat sink
5) Back side heat sink
Completing our look at the major components are the two outer heat sinks that screw onto the front an back heat sink bases. These heat sinks have 2 distinct sides: one side has a long groove for the heat pipe to sit in (see pic above), and the other, outer side (see photo below) has cut fins and slats to increase surface area. These too are made of the same anodized aluminum as the heat sink bases.
With the exception of guidance on selecting the correct pair of heat sink bases, the manual that Zalman includes does an excellent job of illustrating the basics of assembly and installation. The pictures are exceptionally clear and the English text was obviously written by someone who is a native English speaker.
I won't repeat the manual here, but the basic installation procedure is:
1. Remove original cooling solution (the silver HSF in center of the photo below)
2. MAKE SURE THAT THE CARD HAS AT LEAST 2 HOLES THAT CAN LINE UP WITH EITHER HEAT SINK BASE (If your card has no holes you CANNOT use this product)
3. Clean off thermal interface material from GPU
4. Choose heat sink base
5. Apply TIM to GPU core (I used ASIII, but Zalman includes 2 small tubes of white grease)
6. Loosen mounting arms on front heat sink base and line up with mounting holes (do not tighten now)
7. Insert mounting screws through holes in PCB making sure that pre-installed washers remain above the board
8. Using the 2 brass M-F standoffs (bottom left in pic), attach front heat sink to the board
9. Now tighten the mounting arm screws and align the heat sink bracket over the GPU
10. Apply the appropriate, included plastic insulator (not-pictured) to the back of the back side heat sink base.
11. Place each of the two included rubber washers over the threaded ends of the screws coming from the front
12. Loosen the 2 back side heat sink bracket mounting arms and align with brass standoffs
13. Using brass nipples, attach back side bracket to brass standoffs
14. Align front and back brackets to each other
15. Apply white grease to front bracket in the area where it will contact the heat pipe
16. Apply white grease to heat pipe where it will contact front bracket and heat sink
17. Apply white grease to back of front heat sink where it will contact the heat pipe
18. Insert heat pipe into groove with the other end wrapping around to the back of the card
19. Using the 4 screws supplied mount the front heat sink to its bracket-do not tighten fully
20. Apply white grease to the groove on the back bracket
21. Apply white grease to the heat pipe where it will contact the back bracket
22. GENTLY rotate the heat pipe until it sits in the groove
23. Tighten the back bracket mounting arms
24. Apply white grease to the back of the back heat sink
25. Using the 4 screws provided mount the back heat sink to its bracket.
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