Fan not performing as expected :(

Now I have recently made a post about how I am going to buy a new Aerocool DeadSilence 14cm blue led fan. So I can cool my gpu better I'll give you the gist. My gpu was running hotter then I'd like so I thought it was this case fan config here is that bit 



 So My case is a zalman z11 plus. When I bought the case I wasn't really aware of the whole positive and negative pressure thing. Here is a picture of the case and it's fans

You can't actually see it in these pictures but there are 2x exhaust fans, one in each side panel as part of Zalman's unique HDD cooling solution demonstrated in the following picture.



So I thought since there was one intake which most of was probably being taken up by the 2 exhuasts in the side panel never mind the other 2 exhausts at the back of the case. That installing a fan in the bottom (which is the small picture to the left of the internal case picture) as a filtered intake would help allot since

A It was literally pointing the gpu

B it satisfies the whole air should travel in the bottom right to top left and

C I was going to plug it in via molex hence max rpm


Sadly it kind of didn't I used heaven as a benchmark without the fan it hit  max of 76 with about 70% fan speed

with the fan it hit about a max of 74 with a fan speed of about 65%

Here are the comparison pics


Without the fan


With the fan


Without the fan


With the fan



I mean I was expecting more at least about 5 degrees considering it's a 140mm fan running at max rpm facing the gpu with an airflow rating of like 64CFM


I'll attach some pics to see if I did something wrong. When I was taking the pics I felt over the fan and I really didn't feel that much airflow I think I mounted it as a intake right? well here are some pics

(Sorry I know it's kinda hard to see with the blue led)





If you are thinking about clearance there is clearance as you can see


I mean under there can fit about 1.25 tic tac boxes although that reduced a little because of the dust filter. I know this was a pretty long post but still



I would have been more surprised if you had got 5 degrees decreases from pointing a fan at the GPU,,, 

but.. really I am overestimating the power of a fan. I thought a source of fresh air which it was not getting would help

Yes, I think you are over estimating the difference one fan makes in a system that looks like it has perfectly acceptable airflow (the GPU fan can already pull air in from the base, back and front of the it not like it was suffocating). 

And whats the problem with 70 degrees at full load on your GPU, what card is its, as those temps seem fine to me? 

I know it had air but not the cool air I thought this fan would deliver just hot air in the case from the gpu and cpu.

In terms of fresh airflow I didn't think it had allot the considering the only source of fresh air is blocked by two exuasts and a HDD cage.

It's not 70 it's around 74

and it's the temp as well and the noise and no I don't want to tweak the fan profile as I wouldn't be confortable with it running any hotter and some games make it hotter the heaven

It's an msi r7950 Boost OC (960/1250)