Push + Pull with different fan specs question

[Rygar1976]

Hello all - this may be a nitpicky question, but I have time to kill until my new parts arrive.  Through much trial and error, I recently realized that my Corsair h100v2 AIO is dying off after 14 months.  I thought my sudden heat issue was due to needing to replace the liquid metal in my delidded i7-7700k.  I even bought a new all copper IHS from Rockitcool that is 15% larger.  I also used high pressure compressed air and cleaned out the radiator fins.  Unfortunately after all the time, effort and expense, it didn't fix my sudden heat issues.  I used to be fully stable at 5.0 GHz and under 70c while gaming... all of a sudden im about 15 to 20c higher.  Also the time it takes to cool the liquid after stopping a Prime95 test has also gone up significantly.  Rapping my knuckles against the pump once seemed to drop my idle temps as well.  After doing the whole relidding process again I ended up leaving the clock speed set to standard, avx at -2, turbo boost off and C1E enabled to keep temps very low until I get the AIO replaced.

 

Luckily Corsair will do Advanced RMA so I can get a new cooler first and then send mine back.

 

Now on to the main question:  

 

The h100v2 comes with two now discontinued SPL 120mm PWM Fans

Specs:  

• Max RPM: 2700 RPM
• CFM: 74.42
• Dimensions: 120mm X 120MM X 25MM
• Connection: 4-PIN PWM
• Fan Noise: 37.68 Dba
• 4.65 mm-H20

I want to do a push + pull 4 fan setup.  One of the two fans I originally added is starting to die out and were not high static pressure fans anyway, so I decided to buy 2 new fans.  I wanted high static pressure without sounding like a jet engine, though performance is more important than sound.  After checking out the specs on a bunch of different fans, I ended up choosing the Corsair ML120 120mm Mag Lev fans, as they were the closest mm-H20 to the discontinued SPL 120mm fans, but slightly less static pressure:

 

• Max RPM: 2400 RPM
• CFM: 75
• Dimensions: 120mm X 120MM X 25MM
• Connection: 4-PIN PWM
• Fan Noise: 37 Dba
• 4.2 mm-H20

Not a huge difference at all, but I was trying to figure out the best push/pull setup with these.

 

I do push/pull sucking air from outside the case into the inside.  I am guessing my best bet is to use the higher static pressure SPL fans to push and the slightly lower static pressure ML fans to pull.  As I said I realize this is nitpicky, but figured I would ask for thoughts on this setup - or any other ideas as to why I am having sudden heat problems. 

 

Thanks!

 

[TVwazhere]

6 minutes ago, Rygar1976 said:

Hello all - this may be a nitpicky question, but I have time to kill until my new parts arrive. 

-snip-

Honestly, regardless of which side you put the fans on, you'll most likely see no difference in temps. .5Cfm is so little of a different the fans will barely be fighting each other. IT's like a cop pulling over someone going 75mph but not pulling over the guy doing 74.5mph because he was going "too fast" and suggesting there's a noticable difference between the two.

[Dschijn]

It is definitely better to use the same fans for push/pull. Push/pull itself has a very low impact, but you should see 3-4°C lower temperatures with a propper setup. Fresh air (intake gets air from outside of the case) will work best, since preheated air from inside the case will lower the efficiency.

[WoodenMarker]

Your guess seems right. Linus comes across similar results with AF120 / SP120's here: