Thursday, August 22, 2013

[Article] To de-lid my Haswell 4770K CPU or not?

Haswell runs hot compared to SandyBridge. IvyBridge also ran hot, but Haswell runs even hotter than that because of the existence of FIVR (Fully Integrated Voltage Regulator). SandyBridge CPUs had the heatspreader soldered to the die thus having good heat transfer from die to the heatspreader. IvyBridge and Haswell both don't have it soldered. Instead, they have a thermal paste in between the die and the heatspreader. Intel is cheaping out.

The thermal paste itself isn't the issue. The biggest issue is that the "large" gap between the die and the heatspreader that requires a thicker than ideal layer of thermal paste. This gab is caused by the thick layer of glue that holds the heatspreader in place.

The only option is to either lower the temps by lowering voltages thus lowering the overclock OR to de-lid the CPU. That means, you pop open the heatspreader, scrub off the glue, clean off the thermal paste, put a better thermal paste and putting back the heatspreader. If properly done, people have been seeing up to 30°C drop in temps after doing this. THAT is massive.

Lower temps help overclock higher, or run your fans at a lower RPM. But it also lowers the power consumption of the CPU. What? How's that possible? It has something to do with these Tri-gate transistors. More voltage obviously increases power consumption. Higher temps also increase power consumption. Well, if you use power saving features - and your should - this will only happen at full load.

I compiled a list of FAQ below and will keep adding more stuff as time goes by.


Q. How do I pop open the CPU?
A. Currently, two methods exist. The razor blade method and the Vice, Hammer and piece of Wood method.

Razor blade method:

Some people say a sanded (sharpened or thinned out) credit card would be safer than a blade. The issue with the blade is that if you are not being extra careful, you might damage the die or the VRM circuitry if you slip or push too hard into the CPU. Vice method is safer, unless you bang on it with all your might.

Vice and Hammer method:

Be careful not to hit too hard or the CPU will go flying and if it falls on the die, it might get killed. Do not tighten the arms of the vice too much because that may deform the heatspreader. A deformed heatspreader might cause bigger issues than you original had because the cooler base might not get in contact with the heatspreader well. Don't forget that the side of the piece of wood which gets in contact with the CPU needs to be flat.

Q. Which method is easier?
A. The Vice and Hammer method is easier. But it is more expensive if you don't have a vice at home.

Q. How do I clean off the existing thermal paste?
A. Use 99% Iso Propyl Alcohol with a lint-free cloth or kitchen towel. Nail polish remover will also be fine. Once properly cleaned, the die should have a mirror finish.

Q. How do I get rid of the glue?
A. Use a credit card, or your nails, or anything that might help. But get rid of it all, except maybe the stuff in the corners that won't come in contact with the CPU circuit board.

Q. Which thermal paste is the best to apply between the die and the heat-spreader?
A. Cool-laboratory Liquid Ultra (CLU) is the best.

Q. How should I apply is on the die?
A. Put a grain of rice sized amount on the die and spread it with a credit card or a small paint brush so that the whole die is covered. But be careful not to spill anything out of the die. Especially onto the surface mound VRM components on Haswell right next to the die. (IvyBridge didn't have these) CLU is a highly electrically conductive so it will kill the CPU if they come in contact with them.

Q. So how do I protect the VRM components from accidental spilling?
A. Apply a thin layer of Nail Polish on them, or use masking take to cover them, or use an electrically non-conductive paste like MX-4 to cover them up before applying CLU.

Q. Why do we have to put back the heat-spreader? What about bare-die?
A. Very few people will attempt bare-die, because it is dangerous. If you are not very careful when installing the cooler, the die can crack. The die is very fragile. It's not just the weight that is dangerous, but uneven pressure applied on it when installing the cooler. The heat-spreader not only spreads the heat, but also the pressure from the base of the cooler.

Besides, bare-die cooling will only give you slightly better thermals than with the heat-spreader put back on. The risks are not worth the rewards. Plus, you are already taking a big risk by delidding the CPU.

Q. So how do I glue the heat-spreader back?
A. You don't, unless you are trying to sell the CPU without the motherboard. What you usually do is, install the CPU without the heat-spreader in the motherboard socket, apply CLU and then carefully position the heat-spreader over the CPU, put it on the CPU and hold it in place while pushing the socket retention lever down. The retention mechanism will hold the heat-spreader just fine. Sounds ugly, but that's the way it is.

If you are selling the CPU, and just the CPU, you will have to glue it back. I haven't looked into that part yet, so I will update it when I do.

Q. I did all that, but my temps haven't improved. Actually it has gotten worse. What now?
A. You will have to redo it. Perhaps you didn't apply enough thermal paste, or you applied too much. Perhaps the heat-spreader moved when you pushed down the retention lever. Perhaps you didn't get rid of all of the glue. Inevitably temps should drop if done properly. But your miles may vary depending on how bad of a job Intel had done before you delidded.

Q. I want to redo it. How do I clean off the CLU?
A. You can simply wipe it off. You don't need to use any solvent. Just use a lint-free cloth or a kitchen towel to wipe it off. Be careful not to split it everywhere.

I guess that should do it for the time being. I have ordered my CLU, but I don't have a vice, a hammer and a piece of wood. I don't really wanna delid because that would make things harder for me to sell the CPU. Perhaps I would try my luck again with Broadwell. Since I have all the new tech with me with the Maximus VI Hero board, I think I won't need a board swap when upgrading to Broadwell. But that's more than a year ahead. It's the summer right now, and it will get better from hereafter. With my current overclock settings, which I will talk about in another post, the CPU fan speed ramps up to around 1600RPM when I play games such as Crysis 3 and BF3 and when I encode videos using Handbrake. But that's still tolerable. The temps do hit high 70's at these tolerable fan speeds though. Doesn't matter. I don't plan on keeping this CPU for a decade. 

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