Yesterday I bought one of the new 4850's, which I am very excited about putting into my new rig. My case is an Antec 900, which has great airflow, but I decided to try to get the temps down on the 4850 (since they run so high), so I bought this: Arctic Cooling ACCELS1 Rev2 Accelero S1 Rev. 2.
First off, I'm assuming/hoping I have the room in the case.
But more importantly, I have never changed a heatsink on a graphics card before, and would really appreciate a basic walkthrough. For the purpose of the walkthrough, please assume I'm dumb. I built the computer myself, so I can handle myself okay. But still. Assume I know nothing.
1) Make sure you are nowhere near carpet or carpeted furniture, find a nice clean area to work on.
2) Make sure you have good thermal grease available, as disassembling the cooler is going to necessitate cleaning the old grease off and applying new grease to your AC cooler. I use OCZ Ultra high density thermal compound, but OC Freeze is also highly recommended by most people.
3) You will need a small screwdriver (but not too small!) in order to remove the screws from this gpu without stripping them.
4)Right now, before continuing with anything - make sure that you have heatsinks for your memory chips with this cooler; I have never had the need to use an aftermarket cooler - but from where I am looking at the card, the memory chips are definitely in physical contact with the cooler and they have pads that allow them to conduct heat. ed: looking at the picture of the Accelero on new egg, it appears it does come with memory chip heat sinks - 8 to be exact; which is enough for the 8 memory chips near the processor. HOWEVER; the 4850 does require cooling for the chips that are towards the back connector end of the gpu. There will be 8 small black chips directly beside 4 larger gray ones; these will require cooling that I don't think is included with the Accelero.
1) Looking at the front of the gpu, there will be a small fan jack at the bottom right hand corner - first thing to do is unplug that.
2) Flip the car over, altogether on the back of the card there are 12 screws. All of these will have to be removed in order to seperate the cooler and heatsink from the graphics board.
3) You will also see some small semi-sticky pads either sticking to the graphics board, or sticking to the cooler - make sure you save these at least for the time being in case you have problems installing your cooler and its heatsinks, or in case you need to revert to the old cooler for any reason. I can't stress enough the importance of holding onto these so do your best to 1: not damage them and 2: keep /all/ of them.
4) At this point you should have a bare graphics board - now from what I can tell with the AC cooler, it connects to the graphics board through 4 screws which will connect to your retention bracket (THE BIG SILVER X SHAPED DEAL WITH 4 SCREWS ON IT) on the back of your gpu.
5) Apply a star shaped set of thermal grease to the cleaned gpu chip. Make sure not to over do it so that there is gobs. You just want enough to cover the surface. Six to eight nice thin lines meeting at the center should do it.
6) Carefully attach the cooler to your gpu through the retention bracket. This cooler does look a bit heavy so make sure you don't push down on it too much.
7) Last thing, for every memory chip that originally had a thermal pad on it, you will need 1 heat sink. Make sure you have these heat sinks available as I said before or you will more than likely run into overheating issues on your memory chips.
Thats the best advice I can give you, I would feel free to enlist more information from others who are more experienced with mounting aftermarket coolers on gpus - but as I said I do have a 4850 in front of me and the disassembly is pretty straightforward.
The only other thing is cleaning the GPU chip, mem chips and Mosfets.
The GPU chip, use q-tips to gently wipe off as much as you can. Then alcohol. Thats all you really need for the GPU because your going to be using thermal goop. I use MX-2, another well respected thermal paste. The mem and mosfets, about the same process. I prolly used 20 Q-tips to clean my vid card in total.
Start with alcohol, bought cheaply at walgreen or walmart etc. If you use sticky tape to stick the heatsinks onto the chips, alcohol IS NOT ENUFF. You need something better. I and many others use Artic Clean, a two bottle set. Pretty cheap and the bottles last a long time. Just a drop or two on a Q-tip. There are other things that work too, I can't remember what.
If you don't clean it good enuff, the heatsinks can fall off. Bad things happen when that happens. They could fall off a week later.
Here is a link to a thread at xtreme systems I posted late last year installing a HR-03. read thru it or just scroll down about half way till the pics show up. BTW, this is the TOP of the pile when it comes to OCing etc. Great place, #2 to me is OC Forums. Toms hardware, while great for news etc is more of a Radio Shack salesperson kind of place.
Oh, one thing - if you look at your 4850's cooler you will see that towards the back end there is what looks like a bunch of brass colored corn-rows (lol)
Anyways, that is the heat sink for the 8 small black chips and 4 large gray chips that I mentioned before in the "things you need" section of my instructions. This heat sink is attached to the rest of the graphics board heat sink - so there is no easy seperation of it. But you will need /something/ like that (or a cutting torch to remove it to use with your new cooler! lol) in order to cool those power conductors.
Not sure, thats outside my experience. I've disassembled plenty of gpus to replace the thermal grease (including my 4850 and my two gtx260s) - but i've never went shipping for an aftermarket gpu cooler.
There are 2 brackets that push through the cooling fins from the bottom, the cooler assyembly will be facing towards the bottom of the case, and attach to the edge of the card for support. The assy sticks out from the card farther than the stock cooler. There are heatsinks included for the RAM. I dont like the attaching method, two sided tape. RAM has to be CLEAN for them to stick.
The only reason I put one of these on is for the noise, or lack of it. This PC is in my bedroom and I use it to watch TV, Videos, check email etc while laying down.
I did not notice any difference in tempature. Just no noise. Im sure if a fan was to blow directly on the cooler that there would be a great reduction in tempature.