I'm building a new system using an Antec P280 case, an Asus Z77 mobo, and an i5 3570K that I will OC to the 4.2-4.4GHz range. I have a CM Hyper 212+ sitting at home that, while not ideal, should be good enough to cool this system. I'm pretty new to building for quiet, so I'm wondering what fan I should pair with the Hyper 212+, and what, if any, I should add to the case.

I'm going for quiet, not silent. My current system is good enough, and consists of:
P180
C2D E6400 OCed from 2.13->2.93 with stock Intel cooler
GTX 470 + 8800 GTS 640 video cards
2 HDDs
Antec Tri-Cools on low (1000RPM?) at the rear and in the bottom chamber
Noctua NF-S12B FLX at 900 RPM at the top and also clipped onto the drive cage to blow on the video cards (adding one to blow on the GPU was a godsend in quieting down the 470 under load)
Not silent by SPCR standards, but good enough for me as I don't notice it sitting off to the side of my desk, and an example of what I can happily live with.

The Z77 motherboard has 4-pin PWM fan connectors (2 CPU, 3 chassis iirc). Do I need to pair it with 4-pin PWM fans, or will 3-pin PWM do? I feel hesitant to use a fixed RPM fan for the CPU heatsink, particularly as Ivy Bridge seems to run hotter.
For the Hyper 212+, I've seen the Scythe SY1225SL12LM-P recommended ($13 on Newegg), but it's a 3-pin fan. The only 4-pin PWM fans I know of are the Noctua NF-P12 PWM and NF-F12 PWM ($23 on Amazon), which I've seen conflicting opinions about, and the Noiseblocker PLPS, which I'm not too familiar with but is kinda expensive at $30 shipped.
For case cooling, I plan to move the front-most top fan to the front to blow cool air towards the video cards (. Would I need to add anything else, or should that be sufficient? Is there an advantage to using PWM fans for case cooling over fixed RPM fans?

Thanks for your help and advice.

Ok, now I'm confused. This review: http://www.silentpcreview.com/article961-page5.html has that Scythe fan as a 4-pin PWM fan. Newegg http://www.newegg.com/Product/Product.a ... 6835185144, and the Scythe website, list it as a 3-pin. But in the photo, it looks like there are 4 wires there. Am I correct in assuming that the Scythe and Newegg website are wrong, and it is indeed a 4-pin PWM fan?
If so, would that be my best option for the Hyper 212+ headsink, and as additional case fans (should I require them)?

For the CPU cooler of an overclocked Ivy Bridge it would make more sense to use PWM fans, if only because Asus CPU fan headers only support PWM. The Scythe SY1225SL12LM-P is PWM, NewEgg's description of it as three pin is incorrect, it is four pin PWM. This fan works well with the Coolermaster 212. The advantage of PWM fans is that they can have a greater RPM range than 3 pin voltage fans, so it is easier to have a quiet idle and yet still get increased airflow under higher load conditions. Most of the Asus Z77 motherboards support Fan Xpert 2 which allows software control of 3 pin fans to a greater extent than was previously possible. So if you have existing 3 pin fans it is somewhat easier to use them on the chassis fan headers than it was.

The Coolermaster 212 should have come with two sets of fan clips. If so, for overclocking Ivy Bridge I would recommend you use two PWM fans on the 212. This is easier to do if you use one of the upper end Asus Z77 motherboard which has dual (CPU+OPT) CPU PWM fan headers. Also a PWM exhaust fan would make sense. All three fans could be the Scythe SY1225SL12LM-P. Using the Asus BIOS controls and/or Fan Xpert 2 you should be able to fine-tune your cooling to get the right balance of fan noise and airflow.

Thanks. Looking at the photo, I noticed that the fan has 4 wires. I guess Scythe never updated the page for that model, and neither did Newegg.

I was looking at the P8Z77-V or P8Z77-V Pro, both of which have the 2nd CPU PWM header and Fan Xpert 2, and I just checked the 212+ and I've got two clips, so I should be set there.

Should I bother trying just one fan on the 212+, or should I save myself some time by going with 2 fans from the start for better cooling at lower volume?

Getting a Scythe for the exhaust, what would be the best place to put it? Should I put it as top-rear exhaust, and move the two TwoCool fans from the top to the front? Or would it be better to move the two TwoCools to the internal slots? One on the front, one internal? Or leave a TwoCool in the top-rear exhaust, and put the Scythe in the top-front slot? Anyone have a 280 that could chime in with what worked best for them? Would there be any point in orienting the 212+ horizontally, so it blows out the top?

Or should I not even bother trying the 212+ on an overclocked Ivy, and get something like the Scythe Mungen or Thermalright TRUE or TRUE Spirit instead?

Sorry for all the questions, I just like to be sure of things before buying.

For Ivy Bridge overclocking it would make sense to use two fans on the 212 as standard. I am not sure that another cooler choice like the Mugen 2/3 or the True would make that much difference, given that you are only envisaging overclocking to around 4.4Ghz. I think the main thing is to use a two fan cooler. That is made easier by your choice of motherboard as you can plug the two cooler fans into the CPU_FAN and CPU_OPT PWM headers, and control both with a choice of BIOS fan profile and/or Fan Xpert 2. As ever with Asus motherboards, the minimum CPU fan speed is set to 600 rpm by default in the BIOS. You should set this to Ignore (and do the same for the chassis fan headers as well).

The combination of the two Scythe PWM fans on the cooler and one on the exhaust you should give you a quiet idle. As you have Fan Xpert 2 available you have more options with which to deploy the two fans that come with the P280. This will involve plugging both fans into the motherboard chassis fan headers, you may need 3 pin extension cables to do this. The best locations for the fans could be as rear top exhaust and intake. With your choice of motherboard and Fan Xpert 2 you will be able to control the two 3 pin fans individually. For example, you could choose to leave the rear top exhaust off until the CPU reaches a set temperature, maybe something like 60C. This is because top exhaust fans are always going to be more intrusive noise-wise than a rear exhaust. You may find that the Scythe PWM fans will give enough air flow that the same treatment could be applied to the front intake fan. Alternatively you can do something different with the intake fan. This is the big bonus with Fan Xpert 2, PWM fans can be combined with any 3 pin fans that are available or you choose to use to create an integrated cooling system. And although the system is essentially thermally-driven so there will be a degree of automated increase in fan speeds, there is still enough control available to set the balance between temperatures and fan noise-levels to your own personal preference.

Thanks for the all the info.

I also saw that you can mount 140mm fans onto the 212. Would there be any advantage to using Thermalright TY-140 with it, or would the difference be minimal, and I should just stick with the Scythes?

With the Scythes you could expect to see idle speeds of 400 rpm or less. Most users of the Thermalright TY-140 report minimum speeds more in the 700 rpm range. The TY-140 might give you better CPU temperatures, but with higher noise levels than the Scythes.

Ok, thanks, I'll stick with the Scythes.

I've seen elsewhere on spcr that push / pull setups may not be effective on the 212, but I guess that's just a matter of trying out both configs, and going with what works best. Worst case, I can use the 2nd Scythe as an extra case fan.