Discussion Help me make sense of GPU sizes

[reimaru]

I'm working on the concept of a SFF case and trying to establish GPU compatibility but I'm still confused about GPU sizing. Finding measurements is not that hard but I find conflictual information regarding how the measurement is done, with or without the bracket, including the PCI-E contact point or not, not to mention that most free 3d models I found seem to be out of scale and they don't align to the reference full size PCI-E card.

The PCI-E reference document lists full size cards as 111.15 x 312mm, which is a measurement that excludes the bracket. Anyone can confirm this is the way GPU sizes are measured?

Also what would you think is a rational minimum requirement for GPU size for a 20L case?

 

[vinnyoflegend]

This is a fun topic. GPU sizes have crept up inverse to the way rental car companies have downgraded car sizes (passing mid-size sedans off as full).

312mm is probably a fair representation of “average” full size card length these days.

The card height is too conservative though. Outside of some founders edition Nvidia cards and “small” cards the height usually gets closer to 125-140mm especially for “full” size cards.

As for SFF, here’s what I thought was typical lengths:

ITX class 170mm or shorter (sub 5L case) (sometimes low profile. sometimes single slot. Sometimes both)
Mid Size 170 to 200mm(4-5L cases) and dual slot. Height restricted <120mm
Large size. Up to 242mm and dual slot. Sometimes height restricted. <130mm
Full size. Up to 267mm sub 10L case) dual slot ideal but these days starting to see 2.2 and 2.5 slot.

There have been some really efficient designs in SFF in order to fit more typical size GPUs (267-300mm)

Anything else is too large up to 315mm and triple slot

for a 20L case I would expect support for triple slot 315mm cards.

The database at techpowerup of GPU dimensions may be helpful if you are trying to work off of existing/current cards’ dimensions.

 

[reimaru]

This is a fun topic. GPU sizes have crept up inverse to the way rental car companies have downgraded car sizes (passing mid-size sedans off as full).

312mm is probably a fair representation of “average” full size card length these days.

The card height is too conservative though. Outside of some founders edition Nvidia cards and “small” cards the height usually gets closer to 125-140mm especially for “full” size cards.

As for SFF, here’s what I thought was typical lengths:

ITX class 170mm or shorter (sub 5L case) (sometimes low profile. sometimes single slot. Sometimes both)
Mid Size 170 to 200mm(4-5L cases) and dual slot. Height restricted <120mm
Large size. Up to 242mm and dual slot. Sometimes height restricted. <130mm
Full size. Up to 267mm sub 10L case) dual slot ideal but these days starting to see 2.2 and 2.5 slot.

There have been some really efficient designs in SFF in order to fit more typical size GPUs (267-300mm)

Anything else is too large up to 315mm and triple slot

for a 20L case I would expect support for triple slot 315mm cards.

The database at techpowerup of GPU dimensions may be helpful if you are trying to work off of existing/current cards’ dimensions.

Thanks this has been quite helpful. In my design the clearance is roughly 50mm longer than a 4090, while height is ~140 (or ~160 doing a quick mod) and 3 or 4 slots regarding of what is mounted on a top bracket ("top" because is an upside down design). So I guess I'm on the roomy side of SFF.

As for methods of measurements considering what I read I give up expecting something universal, the most common method seems to be "everything except the bracket".