Question GPU orientation?

Amddefector

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Sep 5, 2020
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I've wondered for a while why graphics cards are made with all the components facing downward? I know it makes sense for the cooling fan to suck in air below the card but early examples didn't have a cooling fan! Still the PCB must stop a lot of heat dead in its tracks. I've seen quite a few different answers as to why they are like this but a lot of them are irrelevant now, so why is it still upside down?
 
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InvalidError

Titan
Moderator
The cool air is sucked in, the hot air goes through the case where the hdmi and dp ports are
Many GPUs aren't setup that way though, air blows sideways right back into the case.

The main reason for PCI being upside-down probably was to reduce the likelihood of the first slot mechanically interfering with the CPU HSF - many boards today skip the first slot or only put an x1 there for extra clearance around the CPU socket to accommodate over-sized cooling solutions.

That worked out for the best once the main PCIe x16 interface became integrated in the CPU since it minimizes trace lengths between the CPU, GPU and now first NVMe slots too.
 

Amddefector

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Sep 5, 2020
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Many GPUs aren't setup that way though, air blows sideways right back into the case.

The main reason for PCI being upside-down probably was to reduce the likelihood of the first slot mechanically interfering with the CPU HSF - many boards today skip the first slot or only put an x1 there for extra clearance around the CPU socket to accommodate over-sized cooling solutions.

That worked out for the best once the main PCIe x16 interface became integrated in the CPU since it minimizes trace lengths between the CPU, GPU and now first NVMe slots too.
That makes sense, but if you look back before PCI e or agp when a graphics or (video cards) plugged into a standard PCI port they where still upside down in a time most CPU's where situated in front of the PCI ports not above. Looking at it and PCI cards (of all types) over the years are the same with everything placed on the underside of the card. Maybe the video card followed suit as did the graphics cards that followed? Also back then the computer box layed on its side acting as a table for the monitor maybe the orientation didn't really matter at the time? I totally forgot about ISA cards that had different orientation. I think my first computer had ISA along with its powerful 486 CPU!
 

InvalidError

Titan
Moderator
That makes sense, but if you look back before PCI e or agp when a graphics or (video cards) plugged into a standard PCI port they where still upside down in a time most CPU's where situated in front of the PCI ports not above.
The CPU moving to its modern location above the expansion slot is an ATX thing and Intel likely had ATX in mind when it introduced PCI.
 
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hotaru.hino

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Sep 1, 2020
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I've wondered for a while why graphics cards are made with all the components facing downward? I know it makes sense for the cooling fan to suck in air below the card but early examples didn't have a cooling fan! Still the PCB must stop a lot of heat dead in its tracks. I've seen quite a few different answers as to why they are like this but a lot of them are irrelevant now, so why is it still upside down?
It has to do with convention and compatibility with new and old stuff.

The first expansion slots for PCs, the ISA slot, had the components facing up. However, when PCI was coming out, it was decided the card would be installed with the components facing down. This allowed a PCI card or an ISA card to be installed in the same position. Since then, everything just followed PCI's suit
 
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carocuore

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Jan 24, 2021
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As #6 stated it has to do with ISA/VESA, when those came out there was no "up/down" as most mainstream cases were horizontal and placed on top of your desk, hence the desktop name. Also when PCI came out the 3.3V and 5V slots had different keys, the 5V slot was upside down so to speak in order to prevent you from inserting a lower voltage card.

There were no high end CPU coolers available at the time though, most boards looked like this
 
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Amddefector

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Yeah I remember those boards. If I remember right some had a s single slot with like a PCI hub/riser card thingy. Mine had both ISA and PCI and although the slots weren't interleaved there would have been a problem where both slots met if the PCI card wasn't the other way round. And how I remember it those slots were well used at the time as mother boards didn't have integrated sound or usb etc..... every thing came on add-on cards like PCI and ISA. Case closed.
 

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