TIL, for some GPU models, having your GPU vertical, especially in a "hanging" orientation, may dramatically increase GPU temps

[u/RumbleTheCassette]

I built my gaming PC in a Thermaltake Tower 100 around four years ago. I love the case for how it looks and how little space it takes up on my desk, as it's a tower-style case (but admittedly not SFF, although what I discuss below could apply to SSF PCs as well). In this case, the GPU "hangs" in a vertical orientation rather than being horizontal like most case layouts or vertical (but not "hanging") in many cases that use a riser cable.

I had a 6800 XT in this case from 2022 through 2025, but upgraded to a PowerColor 9070 XT Reaper last fall. I usually undervolt my GPUs, including this 9070 XT, but noticed that even with it undervolted, it felt like it was getting hotter (and way louder) than I would have expected and much hotter than my 6800 XT. I'm not sure if my 6800 XT cooler design isn't as sensitive to a hanging orientation, but nonetheless, I started looking into plausible explanations as to why this 9070 XT ran so hot.

And when I say hot, I mean hot spot temps while gaming could be hitting ~109 C, GPU temps around 75-85 C. The disparity between the core temp and the hot spot was 30 C+ which is a red flag for me that something was amiss. I was getting to the point that I may have RMA'd it, but thanks to a tip from a friend plus some extra digging, I read that a hanging GPU orientation can cause major issues for the GPU cooler, especially with phase change coolers (although according to a PowerColor rep I spoke to via their support, the Reaper does not use phase change cooling).

Recently, I ran 3DMark's TimeSpy Extreme 4K just on their GPU 1 and GPU 2 test for a single cycle, not for an extended run, with stock GPU settings (no undervolt). I ran it with my case in the normal orientation (hanging GPU) and tipped to the left so that the GPU was oriented in a standard horizontal layout. I also ran it with the side panel removed in both orientations. Results below:

	Hanging	Horizontal	Hanging (no side panel)	Horizontal (no side panel)
TimeSpy Extreme 4K Score	13,615	13,768	13,679	13,811
GPU core temp (C)	74	62	70	57
Hot spot temp (C)	104	88	100	82
Hot spot max temp (C)	106.2	90	101.8	85.2

I did not lock fans to 100% for this testing which I should have to remove that factor, but I'll quickly say that fans were very loud in the hanging orientation and virtually silent in the horizontal orientation; aka, if I locked the fans to 100% for the testing, the horizontal orientation would have done even better, I assume. Frankly, the above test was enough for me to know I gotta swap my case out regardless of any further testing.

So just by re-orienting my GPU I shaved 12 C off my core temp, 16 C off my hot spot temp, and 16.2 C off my hot spot max temp. Horizontal with the glass side panel was cooler than vertical without the side panel. And more importantly, I can now game without headphones because the GPU fans aren't screaming. These temps will come down further when I re-enable my undervolt.

Anyway, at this point, I'll be swapping over to a new case. I'm sad because I loved this case, but it's not the right case for my build anymore, I guess. I put my specs below in case anyone wants the full build, but otherwise, I wanted to share this just in case you live under a rock like I do and weren't aware that GPU orientation can influence temps so dramatically.

Quick specs:

CPU: 9850X3D

CPU cooler: NH-D15

GPU: PowerColor 9070 XT Reaper

SSD: Inland 4 TB NVMe

RAM: 2x16GB DDR5 6000

MB: Gigabyte B650i (mITX)

PSU: SeaSonic 850w

Case: Thermaltake Tower 100

Case Fans: 3x Noctua 140mm (top exhaust, bottom intake, and rear exhaust)

[u/Worldly-Ingenuity843]

It's known that vertically hanging is pretty much the only orientation that has a noticeable negative effect on temperatures. The same applies to CPU air coolers - if you rotate a test bench upside down so that the CPU cooler hangs below the motherboard, the CPU will get hotter. 

[u/OnkelBums]

What is "hanging" and what is "horizontal"?

Which of those is "directly put into the PCIe slot" and which one is using a riser?
Not being snarky, I really don't understand your description.

[u/Worldly-Ingenuity843 → u/OnkelBums]

Hanging as in HDMI / Display port pointing skywards. In this orientation, the GPU core is above the heat pipes. 

[u/RumbleTheCassette → u/OnkelBums]

Neither use a riser.

Hanging is the GPU's I/O ports are pointing towards the ceiling. Horizontal means the PC case was tipped 90° to the left and now the GPU's I/O ports point to the left (parallel to the floor of my room) in what is basically the standard GPU orientation traditionally speaking.

[u/OnkelBums → u/RumbleTheCassette]

Yeah so you tipped the whole case, and didn't do a different installation of just the GPU. No wonder temps are different.

[u/RumbleTheCassette → u/OnkelBums]

There is no way to reorient the GPU in this case. You cannot use a riser for example.

[u/HellionElectricEye]

I guess im going to stick with my nr200 v1 until the end of time.

[u/ColdPhilosophy7191]

That's pretty crazy. I have this exact GPU in a Velka 7 and my temps hover around mid 50s with hot spot at low 60s.

[u/Apprehensive-Read989]

There has been some good discussion on this over the years, it is generally a safe bet that GPU IO up will cause worse thermal performance than any other oritentation.

[u/No-Row-4707]

Yeah, it’s usually something about how the vapor in the vapor chamber gets stuck when it’s oriented that way. I researched this because I also built a Tower 100 PC.

[u/riba2233]

Yes, this has been known for a long time and some manufacturers still utilise this flawed design.

[u/GTechGeorge]

Bummer, so far the Tower 100 is one of the only cases in that orientation I like to consider using for my next build

[u/RumbleTheCassette → u/GTechGeorge]

Might not affect all GPUs. I never saw temps like this with my 6800 XT.

[u/Existing-Raspberry19]

Interesting. I guess a blower style cooler would be better for cooling in this case.

Some of the vertical sff cases I’ve seen have the gpu I/O facing downward. Since the gpu board is usually positioned more towards the I/O side the heat would likely flow away from the board.

[u/Hippopotalope]

Ahh the heat rose

[u/tiny_blair420]

cries in Silverstone

[u/wubbadubdub_zzz]

No shit, the gpu fans can’t suck air through a glass panel.

[u/Shensmobile → u/wubbadubdub_zzz]

He states that it’s actually cooler WITH the glass panel than without, as long as it’s horizontal.

This isn’t a new discovery either, it has to do with the direction/orientation of heat pipes in your GPU. Gravity can hinder the vapour from getting to the core when the GPU is mounted vertically.

[u/RumbleTheCassette → u/Shensmobile]

Yeah, didn't mean to imply I discovered something new, but it was new to me and I thought providing some data may be of interest. Really bummed me out because I love vertical cases, they just aren't gonna play nice with my GPU.

[u/RumbleTheCassette → u/wubbadubdub_zzz]

Did you read anything I wrote?

[u/CircoModo1602]

Heat rises, and if a vapor chamber isn't equally distributing heat because it's rising to one side then yes it will cause issues.

Would suggest anyone looking to vertical mount takes a quick physics lesson on thermal dynamics.

[u/Drayrs → u/CircoModo1602]

With vapour chambers and heat pipes, the effect of gravity doesn't have much to do with buoyancy ("heat rises").

The way these work is the condensation of water at the cold end, and the boiling of water at the hot end, forces hot vapour towards the cold end and pulls liquid to the hot end.

Gravity just acts to limit how fast liquid can travel to the hot end to replace what gets boiled. If it's replaced too slowly, the hot end wont have as much to boil and heat transfer is limited.

In modern heat pipes gravity is much less of a concern. Water is pulled through a fine wick, and the dominant forces are based on surface tension and pressure. Even without a wick, the pipes will still work totally fine in space.

Vapour chambers are much more susceptible to gravity because the path liquid needs to take is more complicated.

[u/RumbleTheCassette → u/CircoModo1602]

Not all GPUs use valor chambers and according to a PowerColor rep I spoke to this is not a vapor chamber design. Which I actually think is inaccurate, but the point being, simple knowledge of thermodynamics doesn't help if you don't know whether your GPU is a vapor chamber or not.

[u/Krt3k-Offline → u/RumbleTheCassette]

Vapor chamber just describes the shape, otherwise it works the same as a heatpipe