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I am speaking with manufacturers to have heatsinks made for the Klondike board. Having heatsinks made is going to be less expensive than purchasing and modifying any current solution. I need to know who is planning on purchasing boards, what quantity, and whether or not they would want a heatsink.

Specs are:
100x100x25mm
3mm base
1mm fins
2mm spacing
6000 series aluminum
4 mounting holes drilled, located in center of each 4 chip group.
Flat base/underside

This is a one time deal. Enough heatsinks need to be purchased to cover all the boards, with a few extra. Purchasing additional heatsinks in low quantity will be prohibitively expensive. These heatsinks will not be made available to the general public. They will only be made available to those offering bulk purchasing as I cannot sell these piecemeal. I will be offering them as part of a package to those who purchase chips through me.

Group buy coordinators, Large private buyers, and Klondike resellers need to contact me ASAP.

I suppose this won't work with burnin's boards? Could the stock be chosen such as to be usable by both projects?

Is there really no heatsink out there that will match? I mean there are a huge amount of different models isnt it?
Where are you located again? Or where would a buyer get the shipping from?
Whats the price in which quantity?
And you mentioned drilling holes. I believe bkkcoins wrote that the pcb will have holes so that a heatsink could connect through the pcb and attach to the asic for heat dissipation. Why are holes needed? Wouldnt it be sufficient to make them at the back of pcb with thermal compound?

I don't have the schematics or requirements for burnin's boards. The hole layout and thermal requirements are based on the Klondike board. If he would like to send me that information I can check it out and see if its possible.

One concern with multiple mounting holes is where they would fall on the board in regards to chip placement.

Additionally, more holes will increase the price, though this may be offset by higher quantities.

I think there is a small gap between asic and pcb. Why just do not cool it like avalon design e.g. board is placed in separate housing with fans?

Of course, somebody who want only one board heatsink is the way to go.

Are you sure you want 1mm fins? That'll be very, very sharp. Additionally only a 3mm base isn't much heat storage at all, might want that thicker.

Many of us have personally spent hours searching for a pre-made solution and have not found one. If you have any leads, please let me know.

I am based in Florida, USA. Different shipment locations may be arranged within reason. Ex. the batch split into three parts, with shipments to BkkCoins, Myself, and an EU member.

I am working on pricing now. I cannot get solid numbers without a quantity.

Heat sink holes are necessary to attach the heatsink to the board via the holes BkkCoins has provided.

No. The heatsinks are much too heavy to rely solely on thermal compound for a secure fit. This also puts great pressure on the ASIC chips themselves, and can result in them popping off the board.


Heat sinks work by increasing the surface area of the chip for greater heat dissipation. In order to function, the heat sink must be in contact with the surface of the chip, with no air gaps. The heat sinks Avalon used are attached directly to the backside of the chip.

Every board will require a heat sink. The chips do not have enough surface area to dissipate the heat quickly enough, and will overheat.

Okay, you know better. I just repeated what has been said on bkk thread.
Heatsink goes on the other side, is it?
Here is a copy...

I would like to know if you did the design and if you are experienced in this field (airflow, heat dissipation and so on...).

And i would know what kind of heatsink it will be... one heatsink for a K16 board or 4 heatsinks for a K16 board.

What i wonder is... i understood it the way that bkkcoins makes holes in the pcb under the chips... so that the heatsink can connect to the chip to shuffle away the heat. So the holes for mounting are other holes in the pcb? I only ask because i only have read about the holes under the ASIC's.

Could you say a price per heatsink per ordered quantity?

Edit: Where would the heatsinks be produced, i mean in which country?

This is correct. The chip package has an air gap between the chip and the package top. This is why placing a heatsink on the top of the chip would not work (this is also why you can see the chip when you open the case). Instead, they chose to route the heat dissipation through the board to the backside, where they have mechanically attached an enormous heatsink to dissipate all the heat. The following picture shows this heatsink installed on the backside of the PCB.

https://en.bitcoin.it/w/images/en/thumb/b/b4/Avalon-side-3.jpg/800px-Avalon-side-3.jpg


While I have experience with chip cooling and heatsink requirements, and I know how to read a thermal graph, I am not the only one working on this. I have been working closely with BkkCoins since the beginning to tackle several of the logistical concerns regarding this design.

I have outlined the type of heatsink. Please see the OP.

BkkCoins did not place the hole under the chip. This is impossible. He placed 4 holes on the corners of the board, and a hole in the center of each 4 chip cluster for mounting the heatsink. Without a corresponding hole in the heatsink, there is nothing to attach to. Again, there are no holes under the ASICs.

I need to have a rough estimate for the amount of heatsinks required before I move forward. Asking for a price range between 500 and 5000 heat sinks implies a lack of organization and business plan.

I am speaking with manufacturers in China and the US.

Please reference How heatsinks work (http://www.howstuffworks.com/heat-sink.htm) for questions regarding basic heatsink properties.

Sorry, i overread the setting. So its 4 heatsinks for each K16 board.

I now found what i referred to with the holes under the chips... Its this post: https://bitcointalk.org/index.php?topic=161715.msg2179575#msg2179575
If i understand it correctly it means the holes are filled with heat dissipating stuff so that the chip can connect to the heatsink. The heatsink doesnt have to reach to the chip, its already done in the pcb.

I dont think that asking for prices for different quantities is bad business behaviour. Often they will give a list with quantity to create and the attached price to it. I thought that you maybe have such list.

Forgive my noobness but whats the problem with such heatsink for example: http://uk.farnell.com/h-s-marston/890sp-01000-a-100/heat-sink-100mm/dp/4105977
Its the first result searching "heatsink 100mm". Wouldnt it be possible to drill in the needed holes to attach it at the pcb? I mean the pcb on the other side is flat, theres no parts built in.
The price for these arent low though... i only wanted to ask why such things wont work.

Any heatsink would work potentially, however having the holes pre drilled is a huge timesaver.

If Bkk gives the go-ahead that these will dissipate the heat well enough, given multiple boards stacked together and a fan blowing at them, I'm in for at least 50.

Yes, the thermal vias are necessary to give channels for the heat to pass through to the heatsink. The heatsink physically attaches to the board at the contact patch located directly behind the chips.

The problem with such a heatsink is the ridiculous cost, and hole drilling costs need to be added on top of that.

Also, please note copper standoffs will be required for attaching the board to the heatsink, in order to raise it above the surface of the PCB.

[/quote]
That is correct, there are plenty of options out there, the purpose of the thread is to find the most cost effective solution, which is made possible by buying in bulk.


This particular heatsink is one of the options I am looking at to have custom made holes drilled in. The goal is sub $6 per heatsink.

Edit: quote fail

$6 per heatsink sounds good... though its a bit strange that even at that price the K16 will cost $35 and the heatsinks for it cost $24... I had thought that such things could be pennyware from china or india or similar. Looks like i had a wrong view.

What do you mean with copper standoffs? I thought the heatsink only has to be flat at the bottom, put thermal paste at it and mount it together with the pcb...

I thought that drilling wouldnt be a big problem. I probably could do it myself in some minutes... marking the holes at the back and drilling... aluminium should be possible to drill very easily.

What i dont like so much at the moment is the inflexibility... one batch has to be ordered, thats it... that means you have to plan everything beforehand which i cant... i dont know how many chips i will buy in total. Thats why i would have preferred if bkkcoins could sell the heatsink together with the sets. So i wouldnt need to plan and i could reorder.

I think i will search a bit now... by the way... the heatsink could be everything from 5cm-the border with the holes at the border... so maybe 4x4cm to 0.1x0.1cm. Ill check if there isnt a very cheap offer.

I've also been looking into heatsinks for this board. 100x100 won't do unless you really want to cover up the standoff/mounting holes.

Something like 3.6 x 4 in is what I was thinking. I priced this out, extruded, but without the 4 mounting holes located in the middle of each group of 4 ASICs is about $4.52 in quantities of 1000 and $5.52  for 500.

The is an estimated per piece without tax or shipping. A group buy would be required which I would be willing to undertake if needed.

I am confused.
Is it K16 board dimension at 10cmx10cm, price for those for 300pcs are at 9,3$, steamboat will ask for better pricing? So if you have heat sink at 10cmx10cm it goes on one K16 board?

Summary Preliminary Specs:

10cm x 10cm board
16 chips/board
24A 1.2V, 1A 3.3V supply on board (~32W total)
PCI Express Power connector for use with ATX PSU
USB mini type B connector, no power draw
PIC USB micro controller on board with bootloader for USB firmware upgrades
I2C board-to-board, daisy chain connector
Fan 3 pin connector (on board temp sensor and PWM speed control)

The heatsinks have to be physically connected to the copper thermal ducts on the board. I'm assuming that the board isn't completely flat on the bottom, so you'll need material to contact the copper thermal layer on the bottom of the board, and conduct it into the heat sink. I personally would prefer either one large heatsink which covers all 16 chips; or even better, water blocks for water cooling. Am I the only person who would like to be able to over-clock these, and not have to run a massive box of fans?

Ok, looks like i made an error... the K16 board is 10x10cm... the cooler is 100x100mm, thats the same dimension... so only one heatsink per K16 is needed... but im wondering too now... 16 chips match on 10x10cm? And when the heatsink is the same size then the 4 holes in the edges not only have to hold the heatsink but the whole pcb too. For example mounted to a rack or something.

agreed. 1mm will also bend if there is too much rough handling during shipping/installation.


interesting concept, though for first-gen waterblocks will be overkill. these boards will create less heat then most highend graphics cards, so I would imagine that in an environment with cooler temps and reasonable airflow there would be almost no need to actively cool it at stock speeds. Basic overclocking should be easily dissipated by a 100mm fan if you consider that a 400w GPU is usually handled by 2-3 60mm fans while in an enclosed space.

second-gen would be the time to consider options like liquid cooling

Probably valid points, but fans cost more electricity to run, and they're noisy. Liquid cooling probably IS overkill at this point, but it would allow more units to be stuffed into a case, would be silent, consumes less electricity.

Either way, I've got enough chips already ordered for 5 K16 boards, so whatever's decided, I'll be in for 5. Although, once these are up and mining, I'll be buying more chips, so, depending on price, I'd be willing to order 3-5 times that amount.

I searched a bit now and saw this wholesale website that has quite a lot heatsinks for often very low prices... if we need enough parts thats probably possible. And i think if a company has a minimum of 1000 and you call them saying you only can take 500 im sure they will bite anyway.

For now i only searched for the german word of heatsink "kühlkörper" and added 100mm. Its astonishing how many companies are popping up that create such things for low.
For example this product: http://german.alibaba.com/product-gs/aluminum-heat-sinks-97-w-x60-h-100-l-mm-712256516.html
Though not very much cheaper. Or this: http://german.alibaba.com/product-gs/-font-b-100mm-b-font-1200mm-width-aluminum-extrusion-welded-led-heatsink-for-machine-power-server-electronic-computer-led-pcb-amplifier-581032609.html
The price seems very low for minimum 100mm. But a call cant be wrong.

Or try this search: http://german.alibaba.com/product-list/k%25C3%25BChlk%25C3%25B6rper_100mm/--radiator%2Bbox%2B100mm.html

You can click the companies name too in the list, there are many companies in this business it seems. You can find even more companies with taking away the 100mm.

Its probably best to check out the prices with one or more of these companies.

The heatsink (1 per K16) would mount with 4 fasteners, placed in the middle of each 4 groupings of ASICs. These are not the same as the holes for the standoffs which are at each corner.

Now i see what you mean... the purple dots are the holes in the picture of klondike first post. But the whole board is 10x10cm... thats 100x100mm if im not mistaken. So all 8 holes will be covered with a heatsink of 100x100mm anyway. Or if you want to use the 4 outer holes to mount the board to a case or so, then this would mean you first have to mount the board to the case, then the heatsink, so that heatsink and board arent a unit first. But that cant be because the heatsink needs cooling paste... am i have a wrong thought?

Which gives me an idea, there is no reason to concentrate the heat pads on the heatsink behind the ASICs.  It might be easier to cover the entire heatsink with heat pad and draw the heat away from the entire board instead of just the regions with ASICs.

Ah, now i get it. Heat pads are the vias bkkcoins mentioned. But i believe it wouldnt help much because the vias need contact to the to be cooled unit. The pcb itself is a bad heat conductor. So i doubt that a via that is a cm beneat an asic can take away much heat. And it might be that the vias cost something?

Whats the status here? Since 2 days no new posts? Were the links to the manufacturers in china usefull(-less)?

bkkcoins is suggesting a heatsink of dimensions 90x80mm. You cannot cover the standoff/mounting holes or the thru holes for the PCIe connector (power).

As far as i read at alibaba.com the companies creating heatsinks often calculate in tons, so the weight... that means a smaller heatsink most probably will mean less cost too then.
Plus i didnt understand how to mount the whole unit then into a rack when the heatsink is above the mounting holes at the border. Then the unit has to be mounted together and the heatsink is holding the unit then.

I would also like a quote for this for 100 and 500 pieces. I already have my supplierz but want to verify what he has given me. So far good prices, but i wonder if it's possible to be even cheaper than him.

Thanks,
Steve

Interested in getting some quantity between 100 and 500. I'll get you a hard number as soon as I have one...

https://i.imgur.com/QXPuaEB.jpg

questions, comments, concerns?

OK this is what I would do.  So from Avalon website the dimensions of the chips are 7 mm x 7 mm so I would opt out for individual heatsinks like this one http://www.newegg.com/Product/Product.aspx?Item=N82E16835708011 or http://www.newegg.com/Product/Product.aspx?Item=N82E16835708012.  The first one is 6.5mm and the latter is 10mm.  They are designed to cool video car memory so I think they would be suitable for avalon chips.

This approach has been discussed before. They are not as efficient at dissipating heat, cannot be secured well, and are insanely expensive.

How many fans can be powered? Check the board design... looks like a single 3 pin for 1 fan right? So doing that might not be ideal. I agree with the 1 larger heat sink properly mounted will give you the maximum heat dissipation. Raised or not let us see what BKKCOins comes up with in his tests. I will be sending him 4 heat sinks for testing. Ignore the oversized heat sinks I am shipping as BKKCOINS will mod them to suit his plan but you can use the dimension and spacing for the fins to give you an idea when his test results come out.

https://109.201.133.65/index.php?topic=210635.msg2223916#msg2223916

He will mod them how he thinks and give us all feedback. I am loving the CNC idea and I hope that won't  add too much to my costs here in Indonesia if your design is best steamboart. Fans need some sort of attach point right? Top down blowing directly like a CPU?

Can you give me a link? Im in the process to find out what packaging i need to spread the asics to buyers. Till now i thought the chips will come on a roll but burnin now said he thinks they will come in tubes. I need to know this in order to order the needed packaging...

Sebastian, go to github avalon release, there is chip packaging and dimensions.

Thanks... i thought that is only for building it... i now found the pdf (https://github.com/BitSyncom/avalon-ref/tree/master/PDF) with the measures of the chips... unfortunately i dont find info about how the chips are shipped... in which form. So that i know what packaging i have to buy.

Looks like a good design.  Are you planning on using a thermal pad between the extruded squares and the exposed copper on the back of the PCB or have them contact it directly (maybe with a little bit of thermal paste)?

With that design will you use something on/with the screws for mechanical support to help keep the heatsink in thermal contact with the pads?  Perhaps like an aluminum standoff or insert from McMaster carr, or extrude aluminum there and tap a hole?  Are the holes threaded already?

BkkCoins pointed some things out in his thread so the design is changing to flat, with CNC'd recesses for the PCIE thru-hole connection. This design would have connected directly to the copper w/ paste.

The holes in the center of each group of chips are tapped for a m3 screw. W/ or w/out a spring is TBD.

Steamboat, do you have any plans to also provide heatsinks for the Nano?

Whatever size ends up being chosen, I would think we will want standoffs/spacers to prevent the PCB from curving/warping and loosing contact in the middle due to potential over tightening on the 4 corners. They can be measured to make sure the heat sink still has an interference fit, but keep the warp-age to a minimum. (Think Phat Xbox PCB's  :P )

Hmm, just saw the CAD pic for the K16 today. Good design, renders my above concerns mostly obsolete.

pm sent...

Ill be looking for around 100-200 too :D

What are we looking at for pricing on these?

http://s4.postimg.org/vb1jvdf2x/20130606_121956.jpg (http://postimg.org/image/vb1jvdf2x/) http://s4.postimg.org/4ehkn1w9l/20130606_122011.jpg (http://postimg.org/image/4ehkn1w9l/)

The price for 200 pcs batch is 3.90 EUR
In 1000 pcs I can probably fit in 3.650 EUR

VAT?

excluded

Nice job.

 :'(


:)

Might be good to consolidate all our various extra Klondike threads to one.

1. Casings
2. Controllers
3. PSUs and cabling
4. Firmware  / Mining Software
5. Miscellaneous
6. DIY Build information
7. Pricing and sourcing of PCB, BOM, etc.
8. Heat sinks and cooling

subforum  :P

Beg and u still no receive subforum!

you and your vat....tsk

Glad the recess design worked out for you. I'll keep it in mind.

Yes .
We are going to output 2 versions:
1. With M3 thread on the 55x62 and recess
2. With trough hole 4mm dia and 8 mm dia blind for spring type clamping , with cutout for PCI-e pins

Wot?

I was kinda hoping for a 20% price reduction. A man can dream! :)

This is my first attempt at a simplified model of the K16 I've made using only the Avalon chips. I have them generating 2W each. They are modeled as QFN chips with most of the details and majority of the dimensions correct. I have modeled the lands that go through the board but they may not be meshing correctly so I will continue to look at that. I can add other chips and more detail if I can get the measurements and power output. The more exact I make the model, the more realistic the results will be.

This model uses an aluminum heat-sink which covers the entire bottom surface, the fins and base are 2mm thick - it is based off the heat-sink posted about 20 pages ago. I can alter this to any type of design: change fin size and number, change to fingers, etc. Additionally, this model is cooling only from the heat-sink, i.e., there are no fans or any air movement except that from buoyant convection. It is actually a transient scenario but here I am only using a steady-state model, but I can look at transient.

The temps seem a little high to me, 148 C (300 F), but of course this is without any air movement. However, many GPUs can get to 120 C or more if heat-sinks aren't attached or no air. This was just a first shot and I am going try some other things and recheck this solution, etc.

http://imageshack.us/scaled/large/708/3u8x.png
Avalon chips wire-frame.

http://imageshack.us/scaled/large/819/wqi3.png
Simplified board model with heat-sink.

http://imageshack.us/scaled/large/94/53n.png
Heat-transfer analysis showing temps of chips with no forced convective flow air exchange. Temps of chips reach approx. 150 C while operating at 2W with this heat-sink.

I have since run another model which is based directly from "Heat sink #4" posted by Bicknellski. The initial design above was based on it but I did not have the length of the fins correct. This model changes the overall height from 10mm to 32 mm. There is no airflow, just standing air with the heat-sink portion facing "up" so that the heat can rise away from the board and not get trapped. I accidentally took the picture rotated incorrectly, so please take that into account. The heat is rising not falling. Extending the fins has drastically improved the temperature, reducing it from 150C to 78C.

http://i230.photobucket.com/albums/ee106/PFC4L1FE/sink4_zpsecff6e9e.png
Heatsink #4 - Length 100.00 mm, Width 97.00 mm, Height 32.00 mm, Thickness taken to be 2mm.

http://imageshack.com/scaled/large/402/48d.png
Extending the fins by about 20 mm has reduced the temperature to 78C, approximately a 50% reduction in temperature. (Note: picture was taken upside down - I will update).

The fins are slightly serrated as well or ribbed and there are two raised channels for holding fans or mounting, two fins in on either side.

But that is an amazing result. What is the heat compound simulated in the model?

Also the thermal vias will be filled with an epoxy, I think???, to prevent solder wicking... also the base of the heat sink is 5mm that is pictured pretty sure.

Vigil, are you taking orders for your heatsink when you've perfected it to your liking? If not, could you recommend the best place in the US to get them manufactured? I'm looking for 16.

Note to everyone...

You are best to find a fabrication / extruder site near you. Shipping even 1 of these heat sinks any distance doubles the cost. Find something local. In terms of design you need to develop that. I am hoping we will have something recommended and posted by BKKCoins once he is testing that phase in the GitHub. Start sourcing a local fabricator NOW!

I sent 4 heat sinks of various sizes to BKKCoins and others have also sent heat sinks. Marto sent his heat sink with the holes drilled and notch cut out etc... so follow along in the BKKCOins thread at some point in about 2 weeks we will probably see a heat sink posted there. FANS are needed as passive cooling will likely be a too much especially for those with higher ambient temps.

I am currently trying to get prices for heat sinks locally (Tangerang) and in Jakarta. These links will be helpful for those in Indonesia.

www.superexagraha.com/

www.aluminiumextrusionsatria.com/

www.katalogalumunium.com/consumer-application/AlumuniumHeat%20Sink.html

www.alumas.co.id/product.html

www.pt-alexindo.com/product-range.html

www.alkomandiri.com/about_profile.html

Im not really sure the best approach for cost effectiveness. Has anyone found a 100mmx100mm "standard" style aluminum heatsink that is worth bringing to a machine shop to get the holes drilled? Or is it best to just get them custom made? I live in the Boston area, and this is the best looking place so far I've found: http://www.qats.com/Request.aspx (Advanced Thermal Solutions). They have a plethora of heatsinks and designs pre-fab'd, and accept custom orders. I'll look into it.

Interesting what difference 10mm to 32mm makes. You have an interesting software there.

I got a quote from Heatsink USA for 3.5"(90mm) x 3.5"(90mm)  here. (http://www.heatsinkusa.com/3-500-wide-extruded-aluminum-heatsink/)

Qty. 100, SKU I004, Cut to 3.500” x 3.500” Heatsinks @ $4.36 each = $436.00 (Retail Cost)

Qty. 100, Cut to length charge @ $.20 each = $20.00

Qty. 100, Machine Work @ $5.02 each = $502.00

Total Cost = $963.02 ---> $9.63 each :(

 

Qty. 400 (Retail Cost)

 

Qty. 416, SKU I004, Cut to 3.500” x 3.500” Heatsinks @ $3.92 each = $1,630.72 (10% discount from retail)

Qty. 416, Cut to length charge @ $.20 each = $83.20

Qty. 416,  Machine Work @ $ 3.90 each = $1,622.40

Total Cost = $3,336.32 --> $8.34 each  :-\

 

Qty. 1,200 (12% discount)

 

Qty. 1,250, SKU I004, Cut to 3.500” x 3.500” Heatsinks @ $3.71 each = $4,637.50 (15% discount from retail)

Qty. 1,250, Cut to length charge @ $.20 each = $250.00

Qty. 1,250, Machine Work @ $3.64 each = $4,550.00

Total Cost = $9,437.50 --> $7.86 each  :)

Well i Guess i will be following this tread ,

I have 6 K-16 orderd so I wil want to buy at least 6 heatsink ,
if a fan that goes with them also gets sourced would be verry great

I didn't account for serrations but I think I can apply a surface area multiplier - this will improve heat-sink performance. The two raise channels will probably have little effect on the final result. The current assumption is that there is "perfect" contact between the sink and the board. I think I can add a compound on the interface but have not done so yet.

I will adjust the thickness of the base in the next run. As far as the thermal vias, I am still working on tweaking this. I currently am using copper lands which extend from the pad of the Avalon to the heat sink. Modeling is always a trade-off, it is important to get things as close as possible but sometimes too much detail is not worth the effort. These PCB/heat models can be very accurate (90-99%) so long as the main features are present and the mesh resolution is good enough.

As interesting as producing my own heatsinks would be, I currently have no immediate plans to sell heatsinks, but who knows how things will work out in the future. This was a rough model of a commercially available heatsink posted on another forum by Bicknellski.

Yes, heat-transfer is a game of surface-area. This is why insulating a pipe too much can actually have the opposite effect.

Hello,
is somebody out there who is intending to produce a watercooling solution for BKKcoins K16?

user toolhead created a block for burnins bitburner.
it would be very nice if there would be a solution for the K16s too.

I'm looking into it so as to add it as an option to my build services, but I don't have anything final yet.

http://mittenmining.com

Any news on this yet? I need to get heatsinks ordered for my assembly service ASAP.

Any news on the heatsinks for the k16? If so, lets get a group buy going in the US. I am based in Texas and wouldn't mind ordering 1000pcs to get a group buy started. PM me.

I've been busy sourcing all other parts and barely have had time to think about heatsinks. Seems there are a number of things to keep in mind:

First it needs to contact each of the reverse side of the 16 chips, of which there thermal vias to transfer heat out. Easy.

It should avoid the four side mounting holes. This is easily solved by using a 80x90mm size.

With a flat 80x90mm heatsink is there needs to be a small recessed area so not to short out the PCIe pins. You also need four mounting holes drilled through the heatsink for spring-loaded pins. This is where the cost begins to add up.

I've been floating the idea of using two separate, smaller heatsinks, 30x90mm. I don't know, that might be more expensive in the long run and you'd lose precious surface area. Bkk also gave me the idea of using a copper or aluminum shim to raise the heatsink a bit away from the PCIe pins. I'm just thinking out loud now, feel free to chime in with thoughts.

I ordered 250 heatsinks yesterday. They are 78x100mm. Just wide enough to cover the thermal pads and not covering the mounting holes. They cost about $4.50 each without shipping or tax.

I will have to mill out an area over the thru hole connector and drill/tap the mounting holes myself.