HP 8740w Cooling Overhaul Mod

HP Elitebook 8740w CPU cooling mod

Disclaimer: NOT RECOMMENDED! Attempting this mod can damage your system beyond repair and void warranty. You take the full responsibility for messing with your system!


Materials required:



* an extra dual-pipe CPU heatsink (order from HP Parts Store for 30$), keep the original HS in case of failure.

* Enzotech DDR-C1 Pure Forged Copper Heatsinks (Newegg 10$) or any other heatsinks/heatspreaders 1.5mm thick, as that's the max you can fit between CPU HS and keyboard)

* Arctic Silver Thermal Adhesive

* High performance non-conductive, thick thermal paste with minimal bleed under pressure/temp (I used Tuniq TX-4, for both CPU and GPU)

* tools for holding, cutting and sanding the copper heatspreaders

* plastic/metal tray for prepping the active adhesive substance


The idea:

The square copper plate in the center of the HS is the core point of our experiment.



The goal is to increase the heat transfer from the copper plate to heat pipes, since the pipes are soldered to the plate from above (instead of being submerged into it) thus there's a very little contact area between the pipes and HS.



..................................................
Preparation Step:
..................................................

You'll need to carefully measure and cut the copper heatspreaders into 3 pieces (if you could find a proper copper plate to make a single piece - would be better) in such a way that the pieces don't touch the HS screws. Also, keep in mind, you'll need to be able to insert the modified HS in its place.

....................................................

Main Phase:

AS Thermal Adhesive comes in two tubes that when mixed together will become active and you will have only a few minutes to do the job. Use rubber gloves for this stage and mix the contents of the tubes in a plastic or metal tray. Stir thoroughly using the plastic stick that comes with the package. Next, use the same stick to fill in the gap between the heatpipes
(the black zone on the pic below) with the active compound, then put a thin layer on tops of the pipes (the gray zone).



Next, place the heatspreader pieces over the pipes, press and hold them in place for a couple of minutes, they will be glued to the HS permanently
Sorry for not taking pics during this stage, had just a couple of minutes to make things right - the adhesive cures very fast and there's no second attempt.



Next, install the HS, replace the thermal compound on the CPU and GPU and enjoy the results!

Results:

I wasn't too sure about the effectiveness of this mod but after seeing the temps stay under 78-79C in Prime95 (room 28C) after 30min of stressing, compared to 86C after 10min before the mod. Idle temps went down 2-3C on the CPU.
3Dmark11 maxed at 67C for the CPU and 64C for the GPU.
King's Bounty TAP maxed at 68C for the CPU and after a 24hrs of stressing, gaming and office mode max CPU temp was 71C, which is not bad for a 840QM and 27-30C ambient. I will run more tests later but so far it seems that there is a 6-9C reduction in max CPU temps, which gives hope for upgrading to 940XM and OCing it.

 

Reserved.....

 

you're luky i'm not in your area , cause i would hire you for a pimp my elitebook job !

Excellent pots ..

 

There's clearly an answer to that. SnailMail / FedEx / UPS / DHL / PonyExpress / PackMule ... no need for you to visit in person.

Really loving the post Aikimox, even if I don't think I'll be needed to go that far. I've been thinking I need an extreme processor for the performance I expect, maybe not [I'll be making a post about why in a few days], but in any case I won't necessarily need this. Still great to see it's possible and see it done.

BTW, I'm guessing you never got your D-SLR? The replacement of the K-x I'd mentioned, the K-r, has the only thing that was missing from the K-x, viewfinder feedback. And the K-5 [which was finally everything I expected and I'd been waiting to upgrade to] is keeping up w/the cameras 3x its price. Else if you're open to that pricing territory I'd also recommend the Nikon D7000 which is almost a twin performance-wise to the K-5 even if I'd still give the ergonomics nod to the K-5.

 

^^ D-SLR is postponed for a couple of months I appreciate your advice and will surely dive into it as soon as I can.

 

ok so let's guess what Aikinox can do to my poor 8540w
I5 560M
4b
1600*900

?

Not that much ....a i7 640M that will be less than 10% increase ...
Screen ? i'm interested ..
Ram i'm on 32bits
if he tells me he can put me a I7 Qm on , bingo ...but i know he's not a magician !

 

The only question here would be "How much $$$ are you willing to spend?"

 

Very nice job on the mod, Aikimox; those are some impressive results. The more surface area a heatsink has, the more heat it can dissipate; that's why all those high-end desktop CPU coolers are so big.

I'm curious to see what kind of difference this could make with a i7-940XM + FX5000M-equipped notebook; they get quite toasty with the stock cooling solution.

 

Thanks, Charles!
Wish I had a 940XM to answer those questions.
Also, even though it's possible to use RAM heatspreaders for the CPU HS (as in our case) and probably add many tiny copper plates on top of the GPU HS, the improvement is limited by the small size of the radiators and a single fan.
Still, the improvement is noticeable.

 

i've ordered some parts and will try it with my 920xm overclocked. we shall see what results we get.

atm it sits on almost 100c overclocked by 10% i don't have a 5000M anymore to play with, (work wouldn't let me anyway!) but i can try it with the 2800M

we'll see how it goes. atm waiting for the bits.

 

Haven't you thought about using some kind of larger radiator? on 8510p there is thick black plastic grid to cover the radiator - I think it could be easily cut out to allow fitting larger radiator in.

Dunno, just an idea, maybe old, if yes then sry

btw really nice mod, I LOVE threads like this where people aren't afraid to dismount their expensive equipment!

 

There's no plastic grid to cover the radiator in 8740w. It sits very tight with no extra room, not even a couple mm to play with. There's still some room on the CPU and GPU HS's to add extra copper. The biggest problem is a single fan cooling approach.

 

I've googled few pictures and I think there is this plastic cover (grid) that prevents you from touching the radiator itselft with bare fingers.

 

Do you mean cutting out a part of the bottom area below the radiator? In that case you'll expose the radiator itself and any mild pressure will result in deformities. Not to mention that in that case, you'll not only lose the warranty completely, but also affect the resale value of the system.

 

this grid. it could be cut out and in that place could sit larger radiator. It could be just 0.5 - 1cm of more space but when compared to original size of the radiator it would be like +50%

 

Like I said, it would expose the radiator to deformities (when lifting or carrying the notebook) and totally kill the warranty. But it's an interesting thought, thank you.

 

most definately! but yes, i reckon if we could extend the radiator we would get cooler temps

i'm just waiting to see if HP are going to have dual fan cooling in the next refresh.

My estimated order availability has been pushed back to end of april at least now, so they seem to be keeping things quiet

 

Looking forward to your findings, Bro! That's one of the most important questions regarding the 8750w, IMHO.

 

Nice work Aikimox! Do you still have the old heat sink assembly? Is there any way you can separate the old assembly's heat pipes (soldered on)? I was thinking instead of using the cut-up ram heat spreader on top of the cpu heat sink, you could attach one of the old heat pipes. That way not only could you remove more heat from cpu heat sink but also transport more if it to the fan/heat exchanger. That is if there is enough room. Still excellent work!

 

Thanks, Rollj83

There's unfortunately not enough room for extra heat pipes. 1.5-2mm is the maximum room above the HS. Heatpipes are basically sandwiched by the keyboard from the top and power sircuitry from the bottom.

 

Bump. I'm still uncomfortable about hardcore gaming on this machine. Need to further reduce load temps (our room temp is normally 25-30C). Any ideas?

 

Oh, that reminds me. If you're going to sell this machine, are you going to sell it with the mod, or without? Might be worth mentioning in your for-sale thread if you haven't already.

 

Hello Aikimox!
On my 8540p there is mesh over the intake grill for the fan (the dust filter i believe). Is that mesh present on the 8740w ? To me it seems that if that mesh was removed the fan would suck in more air. I did not remove it on my laptop but i instead ordered the cooling system for the quad core version cpu. To be honest i expected better cooling but at least I got a bit less noise (the fan is different and spins a bit slower). The temps did drop by about 7 degrees on the cpu but stayed the same on the video card.
There were a few problems with the new heat-sink however. The new heat-sink was a little bent and the holes for the mounting screws of the video card were 2-3 mm off, but that was easily fixable by puling on the heat-pipe a bit. The biggest problem was the copper pad that links to the heat-pipe and makes contact to the gpu die. This was about a 0.5 mm to high and did not make contact with the gpu die. I took the thermal pads for the VRAM off, but still no contact. The temperatures with this space in between the gpu and heat-sink went instantly to 105 C under a stress test.
I did not want to send the heat-sink back and I improvised a spacer to fill in the gap. I had some copper sheet from a radiator and fortunately ,after a bit of sanding, that went in and all is well now and temps are at 72 C max for the video card and 78 for the processor, in furmark and intel burn test

 

liquid cooling?

 

I was thinking about that last night. This is ridiculous, but one could run a thin line through the existing vents that detach just outside the vent. When not in use, something thin could be used to maneuver them behind the vent, and fish them back out when needed. Among many other obstacles, you would of course need a very reliable method of attaching the lines without any leaking.

 

Thanks for the input guys! I will go with a more simple way - installing an extra fan into an upgrade bay caddy. Will keep you posted on the progress.
Thanks

 

I have one more ridiculous ... replace the copper heating pipes with silver pipes for better thermal conductivity
Click List of thermal conductivities - Wikipedia, the free encyclopedia then sort by the thermal conductivity column.
I'm actually surprise at what the link above showed me when I sorted the list. I had always thought gold was a better electrical and thermal conductor than silver, for decades.

 

There is a problem with silver though, it can cause static electricity that can probably short circuit the motherboard if it gets in contact. Copper tends to be safer of the two to be expressed naked as a heatsink.

 

If we are going for ridiculous, the why not graphene, or diamonds? But in reality, a heat pipe has a small amount of water which does most of the heat transfer work. I have no idea how much better it would get with silver, but I'm sure the cost far outweighs the potential benefits.

 

Whell, Silver's within the realm of possibility. You'd be there for about a year [or few?] with a batch of pencils and scotch-tape before you pull-off enough graphine to be enough.


Otherwise, water is in them? ??? seriously? Is it circulated too? I'd expect water filling to reduce the thermal conductivity if it isn't circulated, and I never noticed a pump.

 

I just found this out over the weekend when I Googling this just for the heck of it. This shows all you need for a rudimentary understanding (which is all I have). From wikipedia.



The amount of liquid is very small. The pipe is also at a lower pressure than atmospheric so if there is a leak, the air will rush in and supposedly the liquid will evaporate before it can spill out. Pipes are rated for like 100,000 hours of use which is over 11 yrs if on 24/7. And that's pretty much everything I know about heat pipes.

EDIT: found an animation

 

Adding extra heatpipes would be nearly impossible - no room. Also, increasing the heat flow to the radiators would not automatically mean better cooling. The radiators are really small and combined with the lonely fan might become a bottleneck. That's why I'm quite determined to add an extra fan and somehow increase the air circulation within the chassis.

 

@knight love the thermal pipe; didn't know about that. Wonder how hot it would have to be to work though

@Aikimox will be interesting to see if you manage to squeeze another fan into this thing

 

there is a slim fan option via the CD rom bay that could work, i myself was looking into it as an option when my machine gets hot in the summer.

There are ultra slim 9mm thick 120mm exhausts you can buy that can work with normal pc's. i don't think it would be too hard to adapt it to work in that bay

 

Yes, that's the plan. I already got the bay. Looking for the best fan for the task.

 

I don't know how the fan is going to lay out, but if possible, you should try to build a little exhaust chute along one edge of the bay. Forcing air into the laptop cavity with no where to go is not going to be very productive. You'll get a positive pressure buildup that will fight against the incoming air. If you can promote at least a little circulation, the fan will work much smoother (quieter) and the cooling will be better.

 

Here is a quick sketch. When the fan is embedded into the bay and it's working, we'll examine the air circulation patterns and see what can be improved.

 

That's cool. I was imagining a smaller fan (maybe they don't as small as I imagined). There clearly isn't room for an exhaust chute in the bay. Hopefully the body is much leakier than I am imagining too.

 

looking forward to what the temps look like with the additional fan

 

Let's hope. Since I got a spare keyboard, it can be modded a bit to be made leakier, hehe

 

now I have the vision of you typing on a keyboard with holes in the center of each key - guess it would keep your hands warm when you're gaming

 

Are you sure you want to do the airflow that way? I'd almost think you should reverse the air flow from your drawing, because the way it's going in now it might contribute to that positive pressure problem knight427 was talking about. Then again, having it go the other way might end up having it "steal" air from the radiator fin portion... hm. I guess it's going to have to be "experiment" time...

 

Yes, neither scenario looks super optimistic. We may try both if the first one doesn't work. I can't order a single fan anyway, min 3, so it gives us 3 attempts, hehe.

 

Bad news. Tried the second fan scenario on my IBM R40 to see how it works and got very little effect. We would need a proper heatpipes+heatsink implementation together with the fan, to get a significant improvement.

 

Bummer. But don't worry, I have one more idea. I can promise you it is the last cooling upgrade you will ever need on this laptop. Fill your upgrade bay with liquid nitrogen. I can assure you that you will achieve unbelievably low temperatures within just a few moments. Furthermore, your system will never heat above ambient once the initial treatment wears off.

 

Lol, awesome advice!


Guess, I'll be using the cooler pad for gaming after all...

 

You should try using HWinfo to increase the fan speed. I had great results with it! The only drawback is that the fan is probably going to wear out faster, and it's much noisier .

 

He already is. He was one of the very first to try it out when it was introduced.

 

Yes, I even have a preset profile with manually modified fan thresholds (thanks to Mumak) that auto starts with the program. But at 30C room I can't play Crysis w/o the cooler pad.

 

Wow, the cooling system is pretty weak then, if it reaches those temps even with the mod and manual fan control (I wonder how high the 940xm/5000m configuration goes .