This cheapo Antec VSK10 case has horrible GPU airflow, if it can even be considered airflow. At stock speed, my (admittedly cheapest Palit open air dual fan) 1070 Ti were thermal throttling with Doom Eternal, dropping down below 1800 MHz stock boost clock speed. In comparison, my Silverstone FT02 kept everything nice and cool. At stock it maintains 1800 Mhz GPU core effortlessly, I was able to achieve constant minimum of 1920 MHz (+120) when gaming, this was my 24/7 overclock. With voltage increase, I got constant minimum of 1980 MHz (+180) stable and still no thermal throttling. All with factory default fan curve. First, I upped stock thermal throttle temperature from 82c to 88c. Then made a very aggressive fan profile, from stock 62% at 82c throttle temp to 100% banshee at new 88c throttle temp. This stopped thermal throttling but temperature was hovering at 85c and sounds like PC is about to take off. After some investigation, I found the front case fan I thought was delivering fresh air to GPU was actually fighting against the card's hot exhaust. So a cardboard air divider was made. It is to ensure cool air goes down into GPU intake and hot air goes up and away. This dropped temperature from 85c down to 83c. Other changes include an additional cardboard divider to ensure hot air from GPU doesn't go back down into intake fan from the side. Solid rear slot shield replaced with Silverstone open shield (not in pic). Removed the cover for slot shield screws. Front part of top mesh covered so front intake for CPU isn't pointless. Pic below. Currently, I'm considering drilling a couple of holes in the metal shroud to allow more fresh air into GPU intake. (This design appears to be "inspired" by Fractal Define Mini C, which has airflow holes there) Then, may lower the fan down half way into HDD cage, leaving a gap to allow hot GPU exhaust to escape. Although not sure about this as the front of the case is enclosed, so could just be sucking hot air back into the case. Anything else I could do to this case to improve GPU cooling? Would rather not cut holes on the side panel. The case will be laid down in boot of my car with stuff piled on top, side panel holes would introduce FOD and reduce structural integrity.
Plastic, metal, cardboard, I don't care. Ducts are a massive and almost free performance, airflow and noise improvement that are unjustly ignored outside of prebuilds.
How effective is a duct and how do you determine placement without countless hours of testing? Is this effective in many cases or is it correcting a design flaw? I can imagine using a plastic file folder and scotch tape to fashion something if it will have a measurable difference.
The main point of interest is the piece of cardboard immediately after the black intake fan. How effective? 85c with 90% GPU fan down to 83c with about 80-85% GPU fan. How did I determine placement? Look at GPU shroud design and see where the hot air comes out. Place the cardboard to seperate hot and cool air. Is it a design flaw? I would say yes. Open air GPU is designed to dump air into the case, the case has to deal with the excessive air. This case does not have upwards movement from bottom, so hot air gets pushed back into GPU intake. Re further improvement, back of napkin maths: I'm very happy with FT02 style of massively possitive pressure airflow. That is achieved with 3x 180mm fan at 300rpm when idle, about 500rpm under load. I am attempting to do something similar with 2x 120mm in a smaller area. The 120mm need to be running at 600 * 1.5^2 => 1125rpm to shift same amount of air per fan (huge assumption that fan speed vs air moved is linear, and fan design doesn't affect airflow). So it is do-able if I can set the fan curve correctly according to mobo temperature. Or a more bearable 826 with two 140mm fan....... interesting......
