just as the guys saying , what you are try to make it now is throw some money on the trash ,, you probably will spent $70 , $80 , $100 for the new cooling fan , i would sell the HD 4870 and buy a new gpu
Well about replacing your PSU's fan, do take note that doing so will most likely void your warranty. Also, you're going to have to figure out how you're going to crimp the wires, assuming your power supply's fan uses a connector, and if it does, remove the connector from the power supply and you can try and remove the pins from the connector, then remove the pins from their respective wires. Then, get a fan the same size as the one you just removed from the power supply, (get rid of all wires except for red and black, so if you have a 3 pin, you'll only have to remove the white wire) and attempt to crimp the new fan's wires into the pins you just removed, don't forget to put the wires into the exact same places the previous fan's wires were when you put the pins back into the connector, then just plug the fan back into the power supply and you're good to go.
Might want to test the fan for a few minutes using a paper clip to jumper the PSU (connect your power supply to a power source, switch it on and use a paper clip to jumper the green wire to any of the black wires on the 24-pin ATX plug) in case you didn't crimp properly.
Get ready because I've got my rant boots on
He made no mention of wanting an aftermarket cooler, all he said was he wanted replacement fans. You made a completely random statement. A BMW m3 is going to cost more than a washing machine.... Yes, while that is true it has nothing to do with anything. Also, I see where your coming from, saving money by replacing the lubricant in between the bearings but for some oil you could just about buy a fan anyway so why bother? Also, he didn't ask, how can I fix my worn out fan, he's direct - to the point. He wants new fans, not learn how to fix the worn out one's he's got.
What in the heck are you talking about?! I have no idea where you shop for fans but a little 75mm VGA fan isn't going to cost even $30 let alone 70, 80 or above. If perhaps your talking about a completely new aftermarket cooling solution (heatsink + fan) then yes, it could cost that much however he is not asking for a new heatsink or a new cooling solution, all he wants is help finding a replacement fan for his graphics card. Spending $15 on a new fan to fix a graphics card is hardly wasting $ when it costs well over $100 for a new gpu. You mentioned some 120mm fan and its obnoxious decibel rating but gave no link, I'm assuming that was just a mistake.
what are you going on about?! Your talking about swapping pins around, and cutting wires. This isn't bomb defusing 101 m8, this is simple stuff here and a little research goes a long way. Why get a 4 wire variable speed based fan if the stock fan only has 2 wires? Your creating work for no reason. Swapping pins! C'mon man, that's completely unnecessary. Why not just suggest he look up his actually power supply, find that fan and order it off a parts dealer on eBay. DONE. It really is that simple.
Here is a fan on eBay that will fit the 4870 just fine... And it's only $8.50 http://www.ebay.com/itm/75mm-ATI-ASUS-HD-4870-GTS-250-V...
I understand yall want to help, but it doesn't do the poster, and anyone else who happen by looking for information, any good if you post useless, unrelated links and comments. Its a forum, people shouldn't have to scroll through 30 pages of uselessness and random banter to find the nugget of information the original poster requested. Last but not least, take the 2 minutes out of your busy posting day to copy your message into a spell checker online. I shouldn't have to hire the history channels hieroglyphic decipherer to figure out what your saying.