RTX 4080 Hacked Down to Two Slots For SFF Build

Modded RTX 4080 with dual-slot dimensions
(Image credit: TechTaxi on reddit)

A PC and DIY enthusiast has taken to Reddit to show off their home-modded dual-slot dual-fan GeForce RTX 4080, one of the best graphics cards. Redditor TechTaxi also shared some exciting benchmarking, power usage, and thermal test results from before and after modification for your enjoyment.

TechTaxi’s modified dual-slot dual-fan GeForce RTX 4080 design mates the Gainward 4070 Ghost OC cooling shroud with the Gainward 4080 Phoenix GS PCB, with a few modifications to fit. Specifically, a few VRM clearance distances weren’t quite right when the cooler was swapped over, so the smaller cooler had to be milled down in several strategic places (over some VRMs).

What’s the physical difference? Its official product page shows that the Gainward 4080 Phoenix GS measures 329.4 x 141.6 x 69.7 mm. In contrast, the TechTaxi modded version with the Gainward 4070 Ghost OC cooling shroud applied measures 269.1 x 131.8 x 40.1 mm. With such a significant difference in cooler dimensions and mass, one might expect a substantial detriment to essential metrics like performance, thermals, etc.

TechTaxi has produced extensive data charting before and after graphics card modifications with OC, stock, and various power limits in several benchmarks and games. You can see those tables via the Reddit source links. Still, we have mixed the before and after modification 'stock performance' results into one chart below for a better overview comparison.

Swipe to scroll horizontally
Gainward RTX 4080StockModded Stock
3DMark Time Spy Score28,12028,105

Wattage

310.813W

311.549W

Graphics Test 1 FPS

188.75 FPS

186.48 FPS

GPU

56.3 °C

70.5 °C

Memory (VRAM)

54.0 °C

64.0 °C

GPU Hot Spot

67.6 °C

83.3 °C

Cyberpunk 2077 - 3 Cycles

78.88 FPS

77.60 FPS

Wattage

286.573W

286.430W

GPU

57.60 °C

69.44 °C

Memory (VRAM)

57.78 °C

63.28 °C

GPU Hot Spot

66.42 °C

77.14 °C

Average (Gaming + Synthetic)

Row 14 - Cell 1 Row 14 - Cell 2

Wattage

296.433W

295.742W

FPS

212.06 FPS

208.69 FPS

GPU

57.40 °C

70.45 °C

Memory (VRAM)

56.23 °C

65.23 °C

GPU Hot Spot

67.94 °C

81.81 °C

The most crucial thing shown was that the compact modified RTX 4080’s GPU running at ‘stock’ specs was, on average, about 13 degrees Celsius hotter under load (about 23% hotter). The actual temperature measurements of the compact modified graphics card raised no concerns either. Moreover, performance differences were within the margin of error.

Further results shared in the Reddit post give some insight into power limiting and its effect on GeForce RTX 4080 thermals and performance, but that’s another topic.

Overall, TechTaxi concludes that factory-produced RTX 4080 cards with 2-slot (and two fans) designs should be a practical possibility if AIBs were inspired to make them. Including a quiet, undervolted mode out of the box would also benefit SFF builders, reckons the Redditor.

Nvidia’s RTX 40 series has a reputation for being overly bulky. MSI introduced a new Gaming Slim series based upon this perception, but this range includes triple fans, and even the slimmest SKUs at 46mm are thicker than dual-slots (41mm).

Mark Tyson
Freelance News Writer

Mark Tyson is a Freelance News Writer at Tom's Hardware US. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.

  • endocine
    The coolers on the 4080 were all overkill, something more sane could have easily been implemented and still kept the thermals under reasonable control. The size of the GPUs and their power consumption has risen to absurd levels. They are cracking, melting, using way too much power and generating too much heat
    Reply
  • Alvar "Miles" Udell
    MSI makes a 2 slot liquid cooled 4090, could have just used that.
    Reply
  • aberkae
    Alvar Miles Udell said:
    MSI makes a 2 slot liquid cooled 4090, could have just used that.
    yep mine fits in an itx h210 case doesn't throttle even with 150 mhz oc on core and 150 mhz on memory.
    https://photos.app.goo.gl/vcuRQkaSQfS8Vm2g6
    Reply
  • kira-faye
    aberkae said:
    yep mine fits in an itx h210 case doesn't throttle even with 150 mhz oc on core and 150 mhz on memory.
    https://photos.app.goo.gl/vcuRQkaSQfS8Vm2g6
    I mean, an H210 is gigantic for an ITX case, so that's not really saying much.
    Reply
  • jkhoward
    Alvar Miles Udell said:
    MSI makes a 2 slot liquid cooled 4090, could have just used that.
    The size of the heatsink is an old marketing trick, the bigger the better, hence Intel and AMD’s giant CPU boxes.
    Reply
  • umeng2002_2
    Or the rumors about these cards originally using like 600 watts were true.
    Reply
  • WinThenChill
    Alvar Miles Udell said:
    MSI makes a 2 slot liquid cooled 4090, could have just used that.
    The liquid cooled 4090 by MSI is effectively more than twice the size of this modded 4080 though. If you take the measurements of both the card (280x140x43) and the radiator + fan (274x121x55), the MSI is by all means a huge card.
    The modded 4080 has a much smaller footprint and can be used in many small form factor cases that otherwise are limited to 4070 cards at best.
    Reply
  • sycoreaper
    "Dreams of dual-slot, dual-fan air-cooled RTX 4080 GPUs can come true."

    I'd keep the 4 slots over a 20° increase
    Reply
  • Joseph_138
    Look at the difference in those operating temps, though. Over time, that's going to have a detrimental effect on the longevity of the GPU. Performance could also be impaired if it starts throttling. If you're someone who upgrades every time something better comes out, it might not be a problem, but if you're like most people, who keep their cards for several years, you may end up having to replace it earlier than you budgeted for.
    Reply
  • Joseph_138
    Alvar Miles Udell said:
    MSI makes a 2 slot liquid cooled 4090, could have just used that.
    "Dreams of dual-slot, dual-fan air-cooled RTX 4080 GPUs can come true."

    You obviously missed this part. The whole point was to make an air cooled card. Having to install a separate radiator and fan assembly is like adding a second video card, in terms of space, which actually makes it 4x wide. You're not saving any space at all.
    Reply