It looks like this is happening - and about 5 minutes on Google tell me that no one crammed a 4090 into a 5l case as of yet so until someone proves me wrong I'll go with this rather bold headline!
After quite some pondering over the basics and some preliminary testing, I'm reasonably confident that this can work - with the usual 3 challenges in mind:
Power, heat, space - this one will be fun!
Preliminary list of ingredients:
• Case: Skyreach 4 Mini, as usual (yes I will be cannibalizing my last build here)
• Front Bezel: My custom S4 Mini Heat Sink Bezel, machined from Aluminum, anodized black
• Board: Asus Rog Strix B650E-I (more on why that's not a ROG Strix X670E-I later)
• RAM: 2x16 GB G.SKILL Flare X.5 DDR-5 6000 CL32-38-38-96
• GPU: NVidia RTX 4090 FE
• SSD: Samsung 980 Pro 1TB (Gen5 is - at present - a space issue... may evolve!)
• Radiator: AlphaCool Nexxxos 140.v2
• Pump: AlphaCool DC-LT 2600 with Alphacool Eisstation 40-DC reservoir and a 6/8mm soft tubing circuit
• CPU Water Block: the unobtainable original EK Annihilator
• GPU Water Block: Modded Corsair HydroX 4090 FE with custom Plexi top
• Fan: Noctua A14 industrialPPC-3000 with Aquacomputer Quadro for controls
• PSU: Modded SuperMicro PWS804-r, 800w/12V single rail
• Fittings: Predominantly Festo G1/8, with a couple of Koolance NZL ultra-low profile G1/4 elbows between radiator and pump
• Riser: custom-made LinkUp PCIe4 cable
...so no too drastic departure from my last build - cooling, power, and case remain in place, everything transporting electrons at high frequencies is new, and the cooling will need to learn a few new tricks.
And here's the plan:
From the outside, it looks identical to the previous version (it's the same case and bezel after all)...
...and the basic layout is pretty similar to what I came up with for my 3090 & 5950X build:
And as you may see, my intention here is to not start meddling with too many different parts but to keep the motherboard's I/O shield and cooling assembly intact bar for some decorative plastic (my previous builds required quite a lot of modifications to fit the GPU and block - and I had some interference issues resulting from removing parts of the I/O shield) and even leave the board's active VRM cooler in place. Also, I want to use the original ram heatsinks as DDR 6000 without cooling would appear a bit overly ambitious.
To make this work without cutting into motherboard parts or other components, my 4090 / water block combo will have to become smaller and thinner than the 3090 solution I came up with - and I intend to do this by building the world's smallest water block for a 4090. Well - at least smaller than this one, and if @optimumtech did their research well, which I assume, I conclude that I beat Alphacool as what I am currently designing is smaller in every dimension - that's, of course, presuming it works!
As in my previous builds, it will sit on top of the CPU with the first-gen EK Annihilator - out of production since 2016 but still, the smallest AM5-capable block that I am aware of.
So much for the general ambition - let's start by looking at the basics for heat and power:
There is a lot of talk about 1000w being the minimum for a 4090 and top-end CPU - doing the math using the nominal TDP figures, I get to 450W (4090) + 120W (R9 7950X3D) + 65W (rest of the system, on a bad day) - totaling to 635W... so that should be a reasonably comfortable fit with my 800W PSU. Well, it better be, as to date this is still the most compact PSU mod I am aware of, and still, the apparent maximum I can cram into an S4Mini. Conveniently, I have a year-long track record of running a 3090+5950X with this PSU, so rather than starting my calculations from scratch, I can work with the deltas:
The CPU should be not too much of a concern. Even though the IRL power consumption of a 7950x3d with sustained all-core load is a staggering 150W, it's only marginally more than the 136W peak of my current 5950X (which I heavily overvolt for stability reasons - so it's probably quite a bit more) - and, luckily, much less than the 240W loaded power draw of the 7950x.
The 4090, however, comes with more of an uplift compared to its predecessor: IRL, benchmark tests suggest that the 4090 pulls around 420W at 98% utilization - that's giving me some more headroom compared to TDP, on the other hand though, it's considerably more than the 366W IRL sustained load power draw of the 3090FE I currently use on my PSU.
So, altogether still within the theoretical margins or the PSU, but 70W (or around 15%) more than my current build, having an impact on both heat and power.
Regarding heat, I'll be pretty much stuck with my current layout as there is no way to cram more than my current 140mm rad into this build: But with CPU temps in the low 70s and water in the mid-50s under load, I believe it is possible as I have two variables to play with: Currently, the air intake to the radiator is through the case's ventilation slots with about 35% opening ratio. Cutting out the fan projection from the bottom of the case and inserting a thin mesh instead should significantly improve airflow should I run into trouble, and that without tampering with anything visible. And as a second option, lowering the GPUs power limit would suggest being a very effective measure (https://www.hardwaretimes.com/nvidi...performance-at-4k-with-a-power-limit-of-300w/) - this should shave off in excess of 100W of peak load, bringing the thermal load below my 3090/5950X system whilst hardly sacrificing any performance.
But that's the theory -and as usual, there is only one way to find out:
Enter my new 4090FE! I guess I am committed now...
(and a few unboxing shots - looks like they have excess engineering capacity at NVidia directed at inventing rather impressive cardboard mechanics...)
Whilst they are quite a common sight by now, they are incredibly hard to come by in Europe (well, I'm in the UK but that's the same for this purpose): NVidia sold probably 3 to each major retailer and then made them disappear after the first batch - with only 3rd party or reference designs being available. Normally that's not an issue, but if you're in for SFF, you will eventually realize that, like with the 3090s, the FEs have by far the most compact PCB footprint - and that's a decisive enabler for this build.
But we're not there yet:
Here it is in all its voluminous glory next to my 3090 build - beautifully engineered, only a tad too large for what I have in mind for it!
First goalpost is getting it running on my current setup and stressing it to see whether the power setup works (well it better does - no plan B here!) - so I need to build an adapter for my single-rail 12V PSU turning two bullet connectors into 16 pins for a GPU. After triple checking pin-outs (don't want to fry that thing before it fired up once...)
...I get to this beauty...
...which plugs into 3 of 4 8-pins of Nvidias monstrous 12VHPWR (the name is as clumsy as the actual thing) adapter.
Should do the trick.
Frankensteining this together, I should now have a setup that is a pretty good representation of my planned power layout, ready to fire up...
...and: It's alive!
Admittedly, that's low-hanging fruit - the real test is what happens when I stress the system.
Running various stress tests and a few rounds of Port Royal, I get no stability issues whatsoever, and a score of >25,000 indicating that the GPU is happy with the power it can draw:
Also, PSU temps remain very reasonable - so that's the first box "Power" ticked!
Well... apart from that funny smell of heated electronics.
Looking at all temperature sensors I cannot fathom the issue - everything is well within margins, but something is definitely off.
Not intending to burn or electrocute myself, I scan the setup with my temperature gun - and well...
...it looks like my 18AWG wiring between PSU and GPU is not quite happy with the power draw of the 4090
This will definitely need an upgrade - and possibly also new/ different bullet connectors. Technically they are within specs for the wattage I pull, that said, I believe the surface coating on them is cheap and suffered when soldering them on - it looks like the hotspot is near or at the connectors.
Happy I found that out on an open bench - that could have been a flamboyant feature!
Up next: Space and layout considerations - and the water block design (just sent out to manufacturers for quotes...)
After quite some pondering over the basics and some preliminary testing, I'm reasonably confident that this can work - with the usual 3 challenges in mind:
Power, heat, space - this one will be fun!
Preliminary list of ingredients:
• Case: Skyreach 4 Mini, as usual (yes I will be cannibalizing my last build here)
• Front Bezel: My custom S4 Mini Heat Sink Bezel, machined from Aluminum, anodized black
• Board: Asus Rog Strix B650E-I (more on why that's not a ROG Strix X670E-I later)
• RAM: 2x16 GB G.SKILL Flare X.5 DDR-5 6000 CL32-38-38-96
• GPU: NVidia RTX 4090 FE
• SSD: Samsung 980 Pro 1TB (Gen5 is - at present - a space issue... may evolve!)
• Radiator: AlphaCool Nexxxos 140.v2
• Pump: AlphaCool DC-LT 2600 with Alphacool Eisstation 40-DC reservoir and a 6/8mm soft tubing circuit
• CPU Water Block: the unobtainable original EK Annihilator
• GPU Water Block: Modded Corsair HydroX 4090 FE with custom Plexi top
• Fan: Noctua A14 industrialPPC-3000 with Aquacomputer Quadro for controls
• PSU: Modded SuperMicro PWS804-r, 800w/12V single rail
• Fittings: Predominantly Festo G1/8, with a couple of Koolance NZL ultra-low profile G1/4 elbows between radiator and pump
• Riser: custom-made LinkUp PCIe4 cable
...so no too drastic departure from my last build - cooling, power, and case remain in place, everything transporting electrons at high frequencies is new, and the cooling will need to learn a few new tricks.
And here's the plan:
From the outside, it looks identical to the previous version (it's the same case and bezel after all)...
...and the basic layout is pretty similar to what I came up with for my 3090 & 5950X build:
And as you may see, my intention here is to not start meddling with too many different parts but to keep the motherboard's I/O shield and cooling assembly intact bar for some decorative plastic (my previous builds required quite a lot of modifications to fit the GPU and block - and I had some interference issues resulting from removing parts of the I/O shield) and even leave the board's active VRM cooler in place. Also, I want to use the original ram heatsinks as DDR 6000 without cooling would appear a bit overly ambitious.
To make this work without cutting into motherboard parts or other components, my 4090 / water block combo will have to become smaller and thinner than the 3090 solution I came up with - and I intend to do this by building the world's smallest water block for a 4090. Well - at least smaller than this one, and if @optimumtech did their research well, which I assume, I conclude that I beat Alphacool as what I am currently designing is smaller in every dimension - that's, of course, presuming it works!
As in my previous builds, it will sit on top of the CPU with the first-gen EK Annihilator - out of production since 2016 but still, the smallest AM5-capable block that I am aware of.
So much for the general ambition - let's start by looking at the basics for heat and power:
There is a lot of talk about 1000w being the minimum for a 4090 and top-end CPU - doing the math using the nominal TDP figures, I get to 450W (4090) + 120W (R9 7950X3D) + 65W (rest of the system, on a bad day) - totaling to 635W... so that should be a reasonably comfortable fit with my 800W PSU. Well, it better be, as to date this is still the most compact PSU mod I am aware of, and still, the apparent maximum I can cram into an S4Mini. Conveniently, I have a year-long track record of running a 3090+5950X with this PSU, so rather than starting my calculations from scratch, I can work with the deltas:
The CPU should be not too much of a concern. Even though the IRL power consumption of a 7950x3d with sustained all-core load is a staggering 150W, it's only marginally more than the 136W peak of my current 5950X (which I heavily overvolt for stability reasons - so it's probably quite a bit more) - and, luckily, much less than the 240W loaded power draw of the 7950x.
The 4090, however, comes with more of an uplift compared to its predecessor: IRL, benchmark tests suggest that the 4090 pulls around 420W at 98% utilization - that's giving me some more headroom compared to TDP, on the other hand though, it's considerably more than the 366W IRL sustained load power draw of the 3090FE I currently use on my PSU.
So, altogether still within the theoretical margins or the PSU, but 70W (or around 15%) more than my current build, having an impact on both heat and power.
Regarding heat, I'll be pretty much stuck with my current layout as there is no way to cram more than my current 140mm rad into this build: But with CPU temps in the low 70s and water in the mid-50s under load, I believe it is possible as I have two variables to play with: Currently, the air intake to the radiator is through the case's ventilation slots with about 35% opening ratio. Cutting out the fan projection from the bottom of the case and inserting a thin mesh instead should significantly improve airflow should I run into trouble, and that without tampering with anything visible. And as a second option, lowering the GPUs power limit would suggest being a very effective measure (https://www.hardwaretimes.com/nvidi...performance-at-4k-with-a-power-limit-of-300w/) - this should shave off in excess of 100W of peak load, bringing the thermal load below my 3090/5950X system whilst hardly sacrificing any performance.
But that's the theory -and as usual, there is only one way to find out:
Enter my new 4090FE! I guess I am committed now...
(and a few unboxing shots - looks like they have excess engineering capacity at NVidia directed at inventing rather impressive cardboard mechanics...)
Whilst they are quite a common sight by now, they are incredibly hard to come by in Europe (well, I'm in the UK but that's the same for this purpose): NVidia sold probably 3 to each major retailer and then made them disappear after the first batch - with only 3rd party or reference designs being available. Normally that's not an issue, but if you're in for SFF, you will eventually realize that, like with the 3090s, the FEs have by far the most compact PCB footprint - and that's a decisive enabler for this build.
But we're not there yet:
Here it is in all its voluminous glory next to my 3090 build - beautifully engineered, only a tad too large for what I have in mind for it!
First goalpost is getting it running on my current setup and stressing it to see whether the power setup works (well it better does - no plan B here!) - so I need to build an adapter for my single-rail 12V PSU turning two bullet connectors into 16 pins for a GPU. After triple checking pin-outs (don't want to fry that thing before it fired up once...)
...I get to this beauty...
...which plugs into 3 of 4 8-pins of Nvidias monstrous 12VHPWR (the name is as clumsy as the actual thing) adapter.
Should do the trick.
Frankensteining this together, I should now have a setup that is a pretty good representation of my planned power layout, ready to fire up...
...and: It's alive!
Admittedly, that's low-hanging fruit - the real test is what happens when I stress the system.
Running various stress tests and a few rounds of Port Royal, I get no stability issues whatsoever, and a score of >25,000 indicating that the GPU is happy with the power it can draw:
Also, PSU temps remain very reasonable - so that's the first box "Power" ticked!
Well... apart from that funny smell of heated electronics.
Looking at all temperature sensors I cannot fathom the issue - everything is well within margins, but something is definitely off.
Not intending to burn or electrocute myself, I scan the setup with my temperature gun - and well...
...it looks like my 18AWG wiring between PSU and GPU is not quite happy with the power draw of the 4090
This will definitely need an upgrade - and possibly also new/ different bullet connectors. Technically they are within specs for the wattage I pull, that said, I believe the surface coating on them is cheap and suffered when soldering them on - it looks like the hotspot is near or at the connectors.
Happy I found that out on an open bench - that could have been a flamboyant feature!
Up next: Space and layout considerations - and the water block design (just sent out to manufacturers for quotes...)
Last edited:
will follow ofc!
