Community input on case cooling for SLI setup

[Techno-Tortoise]

Hi all,
I recently found a second GPU for a cheap price,
I've never had an SLI setup before and am concerned about temperatures.

So far I have been running with the side off, during testing I found that temps were much better both idle and under load like this. I realise I have an airflow problem, my case has 2 120mm intakes and only a single 80mm out as it stands. To make matters worse my PSU is the Corsair RM series, this wont power on fan until under heavy load. Also the PSU seems to NEVER power on fan if case side is off.

I have set fans to high at rear and low at front in an attempt to evacuate air more efficiently and for the most part all the components above the GPUs stay within tolerable temps.
But I have a few concerns with the Direct CU II heatsinks ejecting heat all over the place, mostly just below and to the right of the CPU cooler intake. Over time I have noticed this make a big difference in the reported CPU temps.

I have been experimenting with 120mm fans both in & out down next to the GPUs and I only get a few degrees change, I tried one on the back of the case at the card slots and got a better result.

I am loathed to start cutting holes in the side of my beautiful aluminium case and am seeking some advice first before going in with the hole saw.
I am hoping however that I could maybe have 1 or 2 120mm intake/s for the GPUs and maybe an 80mm at the hotspot ejecting air but I'm unsure if this would cause flow problems.
I'm more than happy to take any helpful suggestions on how i could proceed.

I'll post a pic of the case set-up and where the main heatspot occurs.

This is what my plan was left unhindered...

AMD FX 3820 8-Core @ 3.5 Ghz - ASUS Sabertooth 990FX rev2.0 - CORSAIR 16GB
Dominator 1600 8-8-8-24 - CORSAIR FORCE3 GS 240GB SSD - ASUS GTX 560 OC Direct
CU II x2 (SLI) - Scythe Katana 3 CPU Cooler - CORSAIR RM 750 Gold PSU - LIAN
LI PC-7 (2006) - SILVESTONE CFP51 Drive Bay - CORSAIR AF120 Front (x2) -
ZALMAN FDB 80mm (x2) Rear & Chipset -

 

[Gam3r01]

Putting exhuasts on the side panel would disrupt flow and might even increase temps. I would go front intake, side intake, and rear exhuast.

Honestly the better choice would be a new case.

 

[zeph_yr]

Putting exhuasts on the side panel would disrupt flow and might even increase temps. I would go front intake, side intake, and rear exhuast.

Honestly the better choice would be a new case.

Yes, get a new case. I recommend a Fractal Design Define R2. Get one of those and put some fans at the top and an intake at the bottom and you'll be good.

 

[Techno-Tortoise]

Putting exhuasts on the side panel would disrupt flow and might even increase temps. I would go front intake, side intake, and rear exhuast.

Honestly the better choice would be a new case.

I would really like to keep this case, I cant afford anything I'd be proud to own right now
So NO on th eside intakes, what about just leaving venting to help expel some of the build up, no fans?
I have a top 80mm exhaust but would need a slim fan because of PSU size.
What i'm really looking for are suggestions to how I could make this case serviceable for this set-up, at least for the time being.

 

[Gam3r01]

Its a no on side exhaust, side intakes would help, but I would say only the two 120mm fans. If you can get a second fan for exhaust that would help too.

On a side note, I know you dont want a new case but you can get some pretty decent ones for under 50.

 

[zeph_yr]

What is that fan between the rear exhaust the the CPU fan doing?

 

[Techno-Tortoise]

What is that fan between the rear exhaust the the CPU fan doing?

The CPU cooler doesn't quite catch the heatsink there so I put that fan on to cool it down for just now until I can cut some intakes on the side panel.

 

[zeph_yr]

What is that fan between the rear exhaust the the CPU fan doing?

The CPU cooler doesn't quite catch the heatsink there so I put that fan on to cool it down for just now until I can cut some intakes on the side panel.

Is it blowing onto the heatsink or towards the open side of the case? If it's towards the open side of the case, you might be disrupting the airflow by blocking the CPU fan.

 

[Techno-Tortoise]

What is that fan between the rear exhaust the the CPU fan doing?

The CPU cooler doesn't quite catch the heatsink there so I put that fan on to cool it down for just now until I can cut some intakes on the side panel.

Is it blowing onto the heatsink or towards the open side of the case? If it's towards the open side of the case, you might be disrupting the airflow by blocking the CPU fan.

It's blowing down onto the heatsink, to be honest I could maybe solve some of my problems by using a different style of cooler... (CPU)

 

[zeph_yr]

What is that fan between the rear exhaust the the CPU fan doing?

The CPU cooler doesn't quite catch the heatsink there so I put that fan on to cool it down for just now until I can cut some intakes on the side panel.

Is it blowing onto the heatsink or towards the open side of the case? If it's towards the open side of the case, you might be disrupting the airflow by blocking the CPU fan.

It's blowing down onto the heatsink, to be honest I could maybe solve some of my problems by using a different style of cooler... (CPU)

I don't really think that's the issue, if it's blowing towards the back of the case it should be as good as any other heatsink. How high are the temperatures, exactly? The graphics cards exhaust out the back, and the CPU looks like it's doing the same thing.

 

[Techno-Tortoise]

What is that fan between the rear exhaust the the CPU fan doing?

The CPU cooler doesn't quite catch the heatsink there so I put that fan on to cool it down for just now until I can cut some intakes on the side panel.

Is it blowing onto the heatsink or towards the open side of the case? If it's towards the open side of the case, you might be disrupting the airflow by blocking the CPU fan.

It's blowing down onto the heatsink, to be honest I could maybe solve some of my problems by using a different style of cooler... (CPU)

I don't really think that's the issue, if it's blowing towards the back of the case it should be as good as any other heatsink. How high are the temperatures, exactly? The graphics cards exhaust out the back, and the CPU looks like it's doing the same thing.

Well, it's just the sucking in of the hot air the GPUs expel.
CPU: 28-36 idle/low use 45-55 under load. GPUs: 30-40 idle/low use 60-70 under load. These temps are with the fans scaling right up to full at 60. BUT when the GPUs are running full over time the CPU rockets up to near 70 and I think it's because it's sucking in all the hot air.