A64/Opteron IHS Removal Guide

hardnrg - 2006-11-18 15:46:21 in Motherboards, CPU's, Gaming
Category: Motherboards, CPU's, Gaming
Reviewed by: hardnrg   
Reviewed on: December 1, 2006
Many of us have been into overclocking, CPUs, and computers long enough to know that the current day Athlon/Opteron CPUs with their heatspreaders are nothing more than the same old CPU die covered by a huge, ungainly IHS. This heatspreader, initially used by Intel on the Pentium 4s, was adopted by AMD but isn't welcome by most enthusiasts. For those of you who want to go oldschool and have your heatsink or waterblock directly contact the CPU die on an Athlon 64, X2, AMD2 or Opteron CPU, check out this guide but read the disclaimer and follow these instructions carefully!

Note: This guide covers an AMD Athlon64 3500+ Venice Core and an Opteron 146, but the removal technique will work on other 64-bit AMD cpus" such as 754 and 939/940 cpus. AM2 CPU's has not been tested yet so I cannot confirm they will work, I do not see why not but you never know.



Disclaimer

This mod has the very real potential to go wrong. You can cut too far and cut of one of the capacitor networks (small surface mounted components around the core) which will either result in a cpu that doesn't work or one that won't overclock as high as it would have done.

Another risk is that during the cutting, you may bend, break, or otherwise damage the pins. Many of the pins are redundant "key" pins so you may get lucky if you break one off, or you might not be so lucky. I almost forgot to mention, the warranty is void when you do this, so if you mess up or you kill the cpu later by too much voltage or whatever then you can't rma it.

Benefits and considerations

Why take the risk?

So what is the point of all this? The idea is for the heatsink or water-block to have direct contact with the cpu core. The temperature improvements will depend on several factors including the extent to which the following is true: the IHS is not flat, the application of the internal thermal interface between the core and the IHS (looks like shin-etsu) is poor, the heatsink/water-block base is not flat.

Heatsink considerations

Because removing the IHS also changes the height of the CPU, you have to consider the effect on the heatsink or retention mechanism. A bolt down heatsink or waterblock should work without modification unless the surface of the sink/block extends over the cam block (where it says "Socket 939") and then you will have to see if the cpu core is at a higher point than the cam block. If it is then the sink/block can lie flat on the core and you have no problem, if the cpu core is lower than the cam block then you will have to sand down the cam block enough so that it is lower than the surface of the cpu core.

If you have a heatsink that uses a clip-on retention mechanism then you can make it work by modifying the base of the bracket.

Modifying a retention bracket

In this guide I'm using a Thermalright XP-120 as an example heatsink, and the base of the plastic retention bracket needs to be modified for the cooler to properly contact the exposed CPU core after we remove the IHS.


These need to be filed down but NOT all the way. You only need to file these down about 2mm (the thickness of the central part of the IHS). Filing down any further will put additional pressure on the core and will also likely cause problems with component clearance on the motherboard. Here you can see the bracket has four small "feet" and then two larger tube-like structures for the bolts.



In the photo above the heatsink bracket is shifted over to reveal one of the components around the socket that is relatively tall. When the bracket is in its normal position the component is underneath the bracket and causes the bracket to rock because the bracket rests on the component (there is one on the other side too). The small mosfet sink that is circled around the top of the picture would pose a problem if i had filed down the feet any further as one of the heatpipes *just* touches this heatsink. If the mosfet sink had caused a clearance issue with the lowered heatpipe, I would have had to file it down. Luckily I didn't.

For this guide I did some benchmark results for 2 different CPUs, my 3500+ and Opteron 146. For my 3500+, I had temperature problems with the IHS on. My load temps soared in excess of 65°C even with moderate vcore values, and a confirmed perfect AS5 application.

3500+ Venice with Thermalright SLK-948u and Vantec Tornado 92mm






9 °C cooler idle and a whopping 22 °C cooler under load is a huge difference after the IHS is removed!

Opteron 146 with Thermalright XP-120 and Panaflo 120mm Hi





Another very respectable result, although not as dramatic as with my 3500+ Venice, 12° cooler under load is a big deal on an Opteron.

Tools

The danger zones

A good idea is to print out a photo of a naked Athlon64 or Opteron to see what is underneath and what kind of distance you have to work with.
Opteron 146 (939)
A64 Venice 3500+

As you can see in the photo, the red lines mark out the edges of the small capacitor networks and the orange lines mark out the additional room you have at the corners. Note that, on the Opteron, along two sides the gap between the black adhesive and the capacitor networks is larger than along the adjacent sides. The Athlon64 seems to have fairly equidistant gaps on all sides. Make a mental note of these distances as well as keeping the printed photo at hand for reference.

Cutting Tool

Now, I used a retractable blade, also commonly known in the UK as a Stanley knife. I'm not sure what they're called elsewhere in the world, but I know they exist worldwide and pretty much every household should have one (shame on you if you don't have one!) A lot of other people have had success with bare razor blades, the type you put in an old-man razor, not a Gillette Mach3! The problem with that is that you have to either be extra careful with the razor, or tape up one side so you don't slice your fingers open. I don't have an old-man razor, and I have a Stanley knife, so the choice was obvious. You might have noticed there is a scalpel type knife in the Athlon 64 photo. This did NOT work because the blade was too thick to fit between the IHS and the cpu circuit board.

Cutting Technique

Support

Ok, so on to the method I use for taking off the IHS. In the bottom of the cpu tray there is some dense foam to protect the pins. I suggest you place the cpu on this foam and press the cpu down onto the foam so the pins are a little more protected than nothing at all. You still have to exercise caution when holding the cpu tightly in position while cutting, I tried to hold the cpu along the edges without pressing the pins in from the sides, and also supported it from the back in the centre (on the foam).

Cutting motion

Here you can see that the blade is lined up along one side. At this moment you can locate the edge of the blade underneath the IHS ready to cut. Leave a bit of blade free so you can rotate the blade as pictured. It is very much like trying to cut the hardest cheese in the world so don't be too worried if you don't cut very far at first. Cut down a little bit and then work your way round a bit on that corner. Then move oto the next corner and so on. Once you've got most of the way through you should be especially careful not too slip and cut too far beyond the black adhesive strip (observing the distances in the photo you printed off).

You should end up with all of the corners done and the remaining part is in the middle of each edge. What I do is get the blade lined up so that only the end part is underneath the IHS and then *carefully* pull the blade along the edge. This is where you have to exercise the most control. I think the key is to gradually cut through all the corners a bit at a time, moving around the cpu, and then cut the sides a bit at a time, continuing to rotate.

Video footage

My digital camera has a video capture feature but the screen power-saving feature was annoyingly turning the screen off so I didn't know that each video capture is limited to 30 seconds regardless of the free space on the memory card. After realising this I managed to do a few takes throughout the process but annoyingly some of the footage didn't get recorded at the end for the final stages of cutting the sides. But I think you'll get a very good insight into how this technique is carried out by watching the video

IHS Removal video