A four/five month follow-up.
Summer is (finally) over and I can move back to overclocking, it was not a particularly hot one here in Finland, thankfully. But it did teach me a lot. There were some hardware changes along the way, and eventually the rig settled to containing 6 gpu's (2 x 5870 and 2 x 5970). Along the way I had a 6990 in the mix, but ended up using it in my dedicated pc, mainly because it just didnt play nice with the airflow in close proximation to ther cards. I have had one major failure: at 3am on a cold May night the entire rig died. Up to this point im not sure what actually happened, but I ended up with a dead motherboard and a dead psu. Both of which had warranties luckily. It was not raining when the failure occurred, nor was there any sign of moisture within. The psu did not entireley die, whenever started it would spin all the fans for 2 seconds or so before giving up. In my opinnion there is no evidence that the unconventional location of the rig had anything to do with this.
Observations and things I've come to realize:
-When I started building this rig I did had not used a single reference-cooled gpu in a dedicated rig. Hence the airflow was and quite far still is designed wrong. What I initially whipped up worked great on my 5870's with arctic coolings solutions. But when I introduced a reference 6990 in to the mix I ended up having to cut an additional opening for it to simply "breathe out". This opening proved to be decent enough solution and even after swapping out the 6990 I am using similiar openings on one side for my reference 5970's to push hot air out.
- Direct sunlight is a mighty foe, the paint I chose was wrong,
white is teh winrar. I did not change this, just ended up adding a make-shift shade for the rig.
- Pollen also is a worthy adversary: any filter I could device for air intakes was either too restrictive, or let it in. In the end I settled with using no filters at all and vacuuming/blowing out the dust once a month or so.
- Operating temperature makes a major difference in power drawn. With my current "between-seasons" setup the rig is working at 2370 Mh/s and depending on the ambient temperature is drawing 940-990W. This is with the current outside temps fluctuating between 17 and 11c. I know this is pushing a 1000W psu, but it's late in the GPU-game and I am determined to maximise my output. Hopefully within a few weeks as the temperatures continue to decline I can add more overclocking, Im certain that I can reach 2500Mh/s at under 1000W once it's cold enough.
- Cheap fans are cheap for a reason 2$ ones from china fail in 1-3 months for me.
- Gasket-sealant is superior to silicone in every way. It lasts better, makes the seams more tight and even looks better.
I added this vent on the roof, underneath within the casing is a 12cm fan blowing out. If i recall correctly this solution alone dropped my temps by 2c. On the door you can see the protection I have for the reference cards "blow air out" - holes and the pipe protecting a newly added big intake fan.
The inside of the "door", with the big intake fan and openings for reference 5970's to breathe out.
The gpu setup and locations I ended up using. I did somewhat give up on cable management.. it just cant be done neatly.
