Optimal Obsidian 650D Replacement Fans

I purchased the Obsidian 650D (CC650DW-1) two and a half years ago, and I can tell the original fans are straining to keep up with the cooling requirements.

 

I opened a ticket with Corsair, and was given some information but not really specific, and they don't even make a fan that will fit/work in the front anymore.

 

SO...having said that, I'm looking for something aftermarket. I already have an awesome Noctua dual-fan beast for my CPU. Figured something along those lines for all of the case fans would be great. As mentioned, I have all the original fans in the unit, but will inventory what's in there if needed.

 

As an aside, Corsair recommended that I use "SP fans on this case instead of AF fans."

 

I'm a little confused about the difference between SP and AF fans, the best/optimal size to use in each position, and the pros and cons of setting up the case in an SP versus AF configuration.

 

I've watched several videos explaining the differences between these two configurations, but honestly, here's what I want:

 

1) All of the components in this case to be kept very well cooled, using air-cooling technology.

2) Price is not really a concern (for reasonable values of X)

3) Noise is not really a concern (I have HEPA filters in each room, that are generally louder than most of my computers.)

4) Dust and dirt being sucked into the case isn't really a concern (I'm a computer tech with a good tech vacuum and professional air blower - I clean my cases a few times per year when they need it)

5) Aesthetics (looks) aren't important, but build-quality is (I want these to last).

 

I just want to make sure that I'm moving enough air through the case, to pull in the ambient (which is always less than 76°F) and get rid of the heat.

 

I'd prefer to buy all of these fans in one place. I shop Amazon a lot, as a Prime member, and like the free two-day shipping. I'm not against shopping elsewhere (Corsair is out because they lack the front-fan by their own admission), I just want to make a single purchase, from a reputable dealer, and replace all of the original fans in this case.

 

I don't necessarily need shopping assistance ("your best deal is at SuperFanMart!") but a comprehensive list of fan makes, model numbers, sizes, and quantities would be awesome.

 

I've noticed that the original top-fan is a single, large unit, but there is space for a dual (radiator?) fan-set. Is it better to have a single big fan, or two smaller fans?

 

Again, I want to keep this air-cooled, although I'm not sure if there are air-cooled radiators, or if that's just for liquid cooled stuff.

 

I do realize that this question has been asked before, and I did a fairly comprehensive search in the forums before I posted this thread. I've been researching this for over six months, and a lot of the companies are changing their fans, so I wanted to get a fresh outlook.

 

Any suggestions?

Wow...anybody? Bueller? :)

Case fans generally come in three types: airflow designed, pressure designed, and a hybrid of the two.

 

Airflow designed fans, like the AF 120/140, have thin, steeply raked blades, and usually more of them. 9 or 11 blades is common. This type of fan will move more air than other type at the same speed. However, the result of the angled blade is a wider conical dispersion of air. This usually is true for the intake side of the fan as well. It is most likely to be quieter than other designs at that same speed.

 

Pressure designed fans, like the SP120, have fewer (often 7), thick and flat blades. They are better at pushing air through resistance, but in free air will move substantially less air than a thin bladed counterpart. These types of fans are better at moving air in a narrow pathway. This is helpful on radiators or small restricted spaces. They also tend to make more air noise at the same speed, although since they are often used against resistance, that can color their true sound characteristics.

 

A hybrid design is a blend of the two. Better pressure and more focused flow than a thin blade fan. Better airflow than a pressure designed fan at most speeds. The new ML series is an example of this design. Most of the 120mm fan market is hybrid and most 140mm pressure designed fans visually appear to be of hybrid design (like a SP140 LED). They are still the best for resistance environments and there are reasons no one makes a larger version of a SP120 in that 140mm size.

 

Since airflow designed fans move the most air, this would seem to be the obvious choice. However, when you place resistance in front or behind it, the volume of air drops quite a bit. Radiators, dust filters, and hard drives all pose some level of resistance. A thin wire rear fan guard - a little. A thick plastic honeycomb rear guard - definitely more. This is further complicated by the speed of a fan. At higher speeds, even air flow fans can move a good amount of air through minor to moderate resistance. However, at low speeds, they are massively hampered. If you put an filter in front of 2x140mm air flow fans at 300 rpm, you can reduce the airflow to almost nothing. Two pressure orientated 140mm fans would move more air through the filter at the same speed, even though they have a design deficit.

 

So, the two questions you need to ask when deciding on what fan type to use are: 1) What kind of resistance will this fan face? 2)What kind of fan speed do I wish to use at that location.

 

Lower is always better for noise purposes, but in some case set-ups a high front intake or rear exhaust speed may be necessary from a cooling perspective and for most people, the load scenario is more critical than the desktop idle cooling environment.

For your specific case, the factory specifications state there is a 200mm front intake fan, a 200mm top exhaust fan, and 1x120mm rear exhaust fan.

 

What kind of cooling issues are you having? Hardware specific? Or general case ambient temperature? Hardware specific can be handled by focused air flow (pressure designed fan) at the necessary spot. Lowering case ambient temperature can be more difficult. If there is a design flaw or some restriction, eliminating that can help quite a bit. However, even if you increase your intake/exhaust flow level by +40 cfm, that may only drop your case temperature by 2C. For most people, that's not worth the extra noise that inevitably comes with higher fan speeds or more of them.

 

How many drives are in the front of the case? 200cm fans are big, slow, and quiet, while moving lots of air. However, they are not good at forcing air through tight spaces. The number of drives in the way makes a difference.

The case will support 1 x 200mm 'Front', 1 x 120mm 'Rear' and either 2 x 120mm, 2 x 140mm or 1 x 200mm 'Top'. From what i remember the top has a clearance of 65mm total to CPU/EPS plug.