I have an ancient Cooler Master ball bearing MGT8012MC fan I'd like to replace, but not a lot of people talk about 80mm fans anymore. Anyone have experience and can make some suggestions? I'm looking at ~2500 rpm. I haven't the slightest idea which 80mm fans have good sound character, other than just trusting brand names like Scythe or Noctua.

There isn't much out there for 80mm. I think the following are your choices

Tier 1. Nexus and Noctua

Tier 2, Scythe

Dark Horse: Noiseblockers

Forget Noctua, you can consider BeQuiet. In my opinion the Silentwings (now Silentwings "2") is the better 80mm fan I've ever had. Noiseblocker are good too, and Coolink not too bad !

Please explain further.

The NF-R8 is "quite old" now, and for its price, there are better fans, such as BeQuiet, NB, etc...
For me the NF-R8 is a "golden oldie"... golden, but in my opinion overtaken by newer fans.

Fans are not like computer components. They don't just get "old" (ie, the technology made obsolete by faster, more powerful chips) -- if it was 15 dBA@1m in 2002, unless production changes were made, a new sample of the same model will be the same in 2012. Unless you have actually compared these various fans side by side (and preferably more than one sample each), it's hard to give much credence to your comments.

Please excuse my english, as I have some difficulties to explain clearly what I meant. I meant that I think there is now better fans than this Noctua, I have compared all the fans mentionned (and some others), but, I reckon, only one sample of each.

As I said, I was quite amazed by the BeQuiet Silentwings fan, and since this fan is (where I live at least) cheaper than the Noctua...

Again, I'm not a BeQuiet fanboy, not at all.

Ah, understood. Time to add that model to our roundup.

I don't know how noisy they were in 2002, but I bought 2 recently and they are rather poor performers. They are not quiet, and the noise they make is not pleasant. They shift a lot of air out in the open, but the flow suffers badly when they are in a well ventillated case (Antec ISK300-65). This requires that I run them quite fast.

I bought the Noctuas to replace two cheap no-name fans that were hard to hear a couple of years ago, when they were new. They became noisy with age, so I used these Noctuas. I wish I knew where I could find the cheap fans I had before.

I find myself looking for a new 80mm PWM fan for use as a case exhaust fan. I have one of the Nexus SP802512H-03PWM fans in another machine. It's not bad; but it could be quieter.

Has anyone tried the Arctic Cooling 80mm PWM fans? They seem to have two offerings: one with ball bearings and one with fluid-dynamic bearings.

Or how about the Akasa AK-FN051?

The Nexus, Arctic Cooling, and Akasa fans are at roughly the same price point ($8–$10). The Noctua NF-R8 PWM, the Be Quiet! T8025-LF-PWM, or the Noiseblocker M8-P would run roughly twice that. I tried the 120mm version of the Noiseblocker fan a little while ago and was not impressed (especially considering the price tag). Are the Noctua or the Be Quiet! fans really worth their premium prices? That is, are they appreciably quieter?

First. Consider changing cases to one with 120mm fan slots. There are really good ones out there and you can even get good cases on the cheap second hand. You would most definitly gain alot both in performance and in cooling levels.

Second. 2500rpm!? Seriously? Why ask at SPCR forums when you are looking at 2500rpm fans. Anything above 1000rpm is noisy no matter what brand so considering 2500rpm means you really arent that noise sensitive and therefore the brand and model you choose wont be that important.

That being said i havent had 80mm fans in a really long time but if i were to get one it would be the Nexus real silent since its recommended by SPCR and it is cheap where i live.

Good luck

Akasa? If they would find a way to make flash drives noisy they sure would. My personal experience with Akasa: Cheapish bought crap from different OEMs all over the world with a brandnew "Akasa"-sticker.

Noiseblocker, be-quiet and Arctic 80mm fans have made a good impressions in the past. The problem i found with 80mm fans: if you volt them down to the point where they please my ears, they seem to nearly stop moving air.

Arctic fans are cheap and have a comparatively low qualitiy, but that allows you to order 5 and return those you do not like. And keep the second best Arcitc fan too, because sometimes Arctic fans will degrade seriously within the first 6 month.

If you happen to find a good Arctic fan you will be equally satiesfied for a fraction of the money.

We need to be past the point where having a quiet PC necessarily means having an expansive noise-dampened case. Of course a quiet PC is a lot easier to get if you do it that way. However, silence isn't the only consideration for a lot of folks. When you can get everything you need to operate a full-featured PC integrated on a Mini-ITX board and gobs of space on a single hard drive (or SDD, even), more and more folks are finding it difficult to rationalize a case full of expansion slots and hard drive bays that will never be used.