Installing a Zalman VF900-Cu Heatsink on a Radeon X800 XT Mac Edition for Use in an Apple G5 Tower

The standard disclaimer - This is how I did it. It worked for me. If you explode your G5, Radeon X800 XT, or your house, car, boat, etc. I am not liable! I am providing information based on my own knowledge and experience. I believe that all steps necessary are included, but if something is missing, I'm sorry in advance. Anytime you work with electronics you should observe caution, and use anti static mats, wrist straps, etc. so as not to damage your sensitive electronic components.

Now, on to the introduction!

I'm pretty new to the Mac scene, but I've been given a pretty nice PowerMac G5 computer tower, and I have finally found the best video card (with an ADC port) to use with it and the Apple Cinema Display. Being a PC user, I had no idea what ADC was, but after some research, here's what I discovered - You don't need a power cord for your monitor! The power comes from the video card, along with a USB connection so you can plug USB sticks n' stuff into your monitor.

This creates a problem, though, because you can't use Apple's cinema display with a video card with standard DVI out only unless you buy the (still) pricey DVI to ADC converter, which runs around $100 used. Also, it has to be a 'Mac' version card - or a PC card that has been 'flashed', but I'm not going into that here because I'm only just starting to learn about that.

That being said, I went on the hunt for the best card to use in my older PowerPC Mac. Again, not being an Apple guy, I didn't know that this run of PowerMac's were the last to use the PowerPC CPU. After this version, Apple went with Intel, and PPC has been left in the shadows of time to fend for itself. You can't upgrade to OS X 10.6, and many plugins like Adobe have dropped PPC support. I like the underdog, though, so this machine is just for me! It's fast, quiet, and has the nicest case I have ever had the pleasure to own.

I finally located a working Radeon X800 XT card for my G5 after a long search and the acquisition of several non-working cards. Don't get me wrong, I don't think anyone was trying to rip me off, but these cards apparently run hot, and that seems to be the problem with the broken cards that I ended up with.

** Just be warned - these cards are pretty finicky, and you may get a good one or you may not! **

After getting a working video card, I began the search for a cooler that would work with the Radeon X800 XT, and I found a new Zalman VF900-Cu Heatsink on Amazon.com! (at the time of this instructable's writing, JURRASIC PHOTOS had 9 left) It included heat sinks for the Video RAM as well, which is a plus, since one of the cards that I ended up with had some fried letters on a VRAM chip on the bottom of the card.

I read all that I could find about this install, but most people just told me about what they did - no pictures. I like pictures, so I decided to make an instructable that had instructions AND pictures.. Hope it helps you old-tech lovers out!

Step 1: Remove the Old Heatsink

Removing the old heatsink is pretty straightforward. I unplugged the fan from the card, flipped it over, then removed the larger screw on the bottom right as you are looking at the back of the card, contact edge towards you.

I removed the two screws holding the heatsink onto the GPU by loosening each one a few turns at a time, first one, then the other. This makes sure you don't place uneven pressure on the chip.

Then gently remove the heatsink with a small twisting motion. Now it's time to clean the GPU off (and the old heatsink as well - you never know when you may need it!)

I use plenty of cotton swabs - first I use dry ones to remove the excess thermal paste, then after it's pretty clean, I use 91% Isopropyl Alcohol to finish the clean.

The old thermal paste was dry and chalky, and I have read that heatsink, or thermal compound only lasts 3-5 years max. This card came out around 2005, so I'm sure it's time for replacement!

Step 2: Check the Fit (in the G5) Before Adding Thermal Paste.

I know, I know, someone will not like this step, but I hate to get it all together with the thermal paste and everything, and then find out something doesn't fit. From what I read online, the plastic & metal thumbscrews are too big and need shaved down. I'm going to make sure that's true before I do it!

Carefully install the 2 nipples as shown in the picture, including the rubber o-rings.

The heatsink is off-center, so make sure you install it so that it doesn't stick over the AGP card edge!

Gently place the heatsink down on the GPU, allowing the nipple ends to pass through the card. Rubber o-rings touch on the top of the card (GPU side), and plastic washers touch the bottom of the card. NO metal touches the card directly (except the bottom of the heatsink on the GPU) - make sure you use all parts noted!

Flip the card over while holding the heatsink onto the GPU, then place it heatsink down in the plastic box that the heatsink came in. This will make the process a little easier, but you still will have to apply some pressure in the center of the card to keep it from tipping off the GPU.

Place the clear plastic washers over each nipple end, then place the springs (larger end toward card) over each nipple end, then start each thumbscrew, and alternate making a few turns on each one to keep even pressure on the GPU. I didn't tighten them down too tight since there's no thermal paste in there yet, they were just snug.

I put everything together for a dry run, and then tried to install it in the G5.

The internet was right... It doesn't fit - it's close, but I don't want to cram it in and put undue pressure on the video card, or the AGP slot.

It looks like I'll have to cut down the thumbscrews that go on the bottom of the card.

Step 3: Trimming Down the Plastic Thumbscrews

I found that the thumbscrew was more stable (for cutting down) if you attach it to one of the extra nipple parts. This allows you to start trimming the thumbscrew without having your fingers way too close to the blade.

With the X800 XT, you only need 2 sets, and this kit comes with 4 sets. This means that you have a couple tries to do this in case something goes wrong!

I used a standard utility knife with a new blade and started cutting around the thumbscrew. It was slow, but care and patience finally won out. Be extra careful here, or you will get to bleed on something really quick!

After I got both of them cut down even with where the metal started, I re installed the card and it fit - but the thumbscrew on the right (as you look at the card installed) was still a little too long. The thumbscrew on the left touches lightly on the metal plate, but I'm leaving that one alone because it's not putting much pressure on the video card - plus it guarantees room for the VRAM heatsinks!

Before I applied the VRAM heatsinks (the next step), I made sure that there was enough clearance between the bottom of the card and the metal divider plate inside the G5, and there was plenty. To do this, you can install the card, then just slide the heatsinks under the card and check the clearance. I'm not sure why most of the instructions that I had read online stated that they didn't use the VRAM stick-on heatsinks on the bottom VRAM chips because there wasn't enough clearance.

If you decide to file both thumbscrews until they don't touch the divider plate, make sure to check the VRAM clearance on the bottom before you stick them on! Having the one on the left (viewed as the card is installed) touch lightly keeps the card supported up just a tiny bit for that extra clearance.

Remember to loosen the thumbscrews a little at a time, one at a time to keep more even pressure on the GPU.

I loosened both thumbscrews almost all of the way, then removed the thumbscrew that needed a little more taken off.

I used a crosscut file to file it down, metal and all, and after a few minutes I had it finished. It doesn't take much, but those tolerances are really close and I wanted to make sure it fit as well as possible.

Step 4: Install the RAM Heatsinks, and Then the GPU Heatsink/fan Assembly

Remove the already loose thumbscrews and remove the GPU heatsink. Make sure to get the plastic washers and springs all collected from the bottom of the card.

Now you are ready to install the VRAM heatsinks.

I finished the final clean on the GPU, then went ahead and applied the thermal paste to the GPU. I didn't use what came in the pack. Instead, I used Arctic Silver, which has worked well for me in the past.
Yes, I use my finger to apply it... I place a few small blobs around the center of the GPU, then using a swirling motion, I spread the paste out to cover the entire GPU. Again, this has worked well for me, and I have done TONS of CPU's, GPU's, etc.

I cleaned each VRAM chip with 91% Isopropyl Alcohol and let them dry, then peeled the blue backing off of each small heatsink and placed them firmly on each chip - there are 4 on the bottom and 4 on the top. I tried to orient them in such a way that they didn't get too close to the AGP slot edge, and I tried to keep them away from any capacitors or other larger items on the board.

I did the 4 VRAM chips on the top first, then placed the GPU heatsink on next.

Here's where you finally get to install the GPU heatsink for good!

If you did the dry run install, you will see a faint outline of the GPU on the bottom of the heatsink. Place a small amount of thermal paste on the heatsink and swirl it out to the edges of the outline.

I found it easier to use the plastic inner box that the heatsink came in to work on the bottom of the card, so have that ready before you proceed.

Make sure the nipples and o-rings are installed correctly (step 2).

The heatsink is off-center, so make sure you install it so that it doesn't stick over the AGP card edge!

Gently place the heatsink down on the GPU, allowing the nipple ends to pass through the card. Rubber o-rings touch on the top of the card (GPU side), and plastic washers touch the bottom of the card. NO metal touches the card directly (except the bottom of the heatsink on the GPU) - make sure you use all parts noted!

Flip the card over while holding the heatsink onto the GPU, then place it heatsink down in the plastic box that the heatsink came in. This will make the process a little easier, but you still will have to apply some pressure in the center of the card to keep it from tipping off the GPU.

Place the clear plastic washers over each nipple end, then place the springs (larger end toward card) over each nipple end, then start each thumbscrew, and alternate making a few turns on each one to keep even pressure on the GPU. Keep this up until both thumbscrews are tight.

Now you can install the 4 VRAM heatsinks on the bottom of the card while it sits face down in the plastic box indentation.

For best results, don't touch the VRAM chips once they are cleaned, and don't touch the bottom of the stick-on heatsinks once you peel off the plastic protective cover!

I just sat the little Zalman sticker in there because it looks cool!

Step 5: Choosing How You Want the Fan to Work - Zalman Fan Mate or On-board Video Card Fan Controller?

If you're OK with using the included 'fan mate', which is a little box that you stick on somewhere outside the case that controls fan speed, then you are almost done. Just plug the fan into the fan mate, then plug the fan mate into something that will supply it with 12V.
Many people online tapped an extra connector from the DVD drive to use for this purpose.

I didn't want to do that. The X800 XT's latest BIOS update included some extra fan control information, and I wanted to take advantage of that. Plus, I didn't want to have to change the fan speed when I needed more cooling - that's the job of the on-board fan controller!

You can see the different style plugs on the original fan, and on the Zalman fan.

I cut the connectors (near the plug end) from each fan first, then removed the wires from the video card's fan plug (you can gently lift the plastic tabs on the other side of this plug, then pull the wire out.

Next, I cut the wires flush with the metal connectors, and then soldered each wire to the correct connector. I followed the wire colors from the video card fan (on the right) , which are (from the picture, top to bottom) White, Black, Red. This is a different order than the Zalman connector.

After soldering each wire onto the top of each metal connector (because that's where the extra room in the plastic plug is), I placed the wires back inside the plastic plug end. I checked to make sure that the connections worked by plugging in the fan to the card, then using a multimeter and probing the bottom where the connector comes through the card, and the top where I soldered the wires to the metal connectors.

I tried to solder the wires onto the bottom first (picture with plate and wires) but they wouldn't fit back into the connectors - so I had to redo all three!

Everything fit well inside the G5 case, and I left the wires long just in case I needed to do something different. As it turned out, everything worked great!

This took me a pretty decent amount of time to do, but I'm happy with the results! Yes, it does block the slot above it, but I wasn't going to plug anything in there anyway - unless it's a super short fan card!

** Remember, it's always a good idea to power cycle the card a few times after everything is installed. I like to run some games, play a video, then let it rest, then do it again, then power off and let it cool.
Repeat a few times to get the thermal paste on its way to being settled. **

After a couple of days use, I would pull the card and make sure the thumbscrews are still tight - they may need a little tweak.

The only sad ending here is that I don't actually know how hot the card is running now (or before), because no one bothered to write a program to get the GPU temp. Apple didn't include it in the ATI Displays tool. I have written the authors of several ATI video card programs (PC and Mac) asking for assistance, but so far no one is interested in working on this, or sending me their source code so that I could try to do it myself. If anyone is feeling helpful, I would appreciate any assistance you could give.
Old tech or not, it would be cool to have.

If you have a different card that is supposed to work with this Zalman cooler, or you need more details, head to this link to get the official User's Manual:

** Update 2019! - new link to the user manual! **

Zalman VF900 User Manual (2019 link)

Thanks! I hope you have enjoyed this instructable, and that it helps you do your own project more smoothly.