Need advice with overheating almost ready NCASE build

Hi!
I seek some help with my current build. I am by far not an experienced persion if it comes to mITXs so I went with was modified version of this one

MoBo: Asus Z97 Plus mini ITX
PSU: Silverstone 600W SST-SX-600-G
My relevant changes:
CPU: i7-4790K colled with:
Noctua NH-D9L and Noctua NF-A9 PWM
GPU: Gigabyte 980ti G1 (no water cooling)
HDD bracket : double 3,5 HDD (WD caviar green 2TB and 3TB)
2 SSDs

Was to add fan or two at the bottom as intake but haven't bought them yet and initial build runs made me think that they just won't be enough ( HDDs are very tightly packed and they are constantly between 45- 50 degrees celsius, CPU is near 50 and GPU 60 at idle state of system)

Should I switch card (if I still be able due to the shop return policy) to the 980ti reference with the rear exhaust and will it be enough with additional intake fan at the bottom of the case or is there any better solution for overheating in my system ? Some good single bracket slim water cooling for my 980ti or anything that could prevent me from returning already bought components.

Ideally I would like to keep two HDD drives if it's possible or at least one and use second in docking station.

Will love to hear your suggestions

I wouldn't call those temps "overheating", since the fan controllers probably turn the fans off or low speed when idling. Overheating would be if your system exceeds 85-90 deg c while under load (you could test this). Idle temps don't mean anything as long as they are under ~75 deg c. Your setup should be fine as is, just check temps under load.

I think his concern is with the HDD temps, which are fairly high.

The GPU is the problem, since it's dumping all its heat in the case. The only options are 1) switch to a rear exhaust GPU, or 2) install an Accelero Xtreme on the GPU or remove the stock fans, and put a pair of 120mm fans on the bottom blowing out. If you do the latter, you'll probably want to bridge the gap between the heatsink and fans with a duct of some kind, like stacking some 120mm fan gaskets.

Edit: never mind I misread your post.
But stacking 120mm fan gaskets also means getting extremely long fan screws if the gaskets are between fan and bottom of case, The maximum I know is 20mm.
Unless the gasket are screwed in from the top of the fans, but I've never tried that.

My GPU with Arctic Accelero Xtreme and two Noctua 25mm thick fans sit flush, without the need for any gaskets. I'd even goes as far saying the silicone dampers at the edges of the frames have some force applied to them.

Necere said:

I think his concern is with the HDD temps, which are fairly high.

The GPU is the problem, since it's dumping all its heat in the case. The only options are 1) switch to a rear exhaust GPU, or 2) install an Accelero Xtreme on the GPU or remove the stock fans, and put a pair of 120mm fans on the bottom blowing out. If you do the latter, you'll probably want to bridge the gap between the heatsink and fans with a duct of some kind, like stacking some 120mm fan gaskets.

Click to expand...

Yes, the hdd temps are my biggest worry.
Under heavy load (5min long test)
HDDs: 50-54 degree
GPU: around 80
CPU: around 70

If I go with the Accelero Xtreme wouldn't the problem with the GPU damping heat into the whole case still be persistent ?
EDIT:
Sorry , missed the "blowing out". But anyway. Need to check hdd temps without and gpu installed. They are really tightly packed with all the cables.