Custom_MOD FLEX mini #001 (8700k Ultra GTX 1080)


Average Stuffer
Original poster
Jun 8, 2017
Hi guys, i just got my Custom_MOD FLEX mini and i wanted to share my experience with this cute case and SFF building. (And sorry for my poor English, i am French :D)

It's a long time now, i m looking for a realy small case that i can use as main PC and travel with.
So, I want something :
- As small as possible that i can put it in a backpack.
- Using only standard pieces (no custom PSU, no mxm GPU...) except case :D
- Without compromise on gaming experience and compute power (powerfull GPU and good CPU)
- Quiet and not too hot (as much as possible)

5 years ago i made my first SFF build
I used a silverstone sugo SG05 with those specs:
- CPU : Intel i7 3770k oc to 4Ghz
- GPU : PNY GeForce Gtx 680 (Very tight fit !)
- MotherBoard : Asus P8z77-i Deluxe (Dead now, replaced with an Asus P8h77-I)
- Ram : 2x8 Gb G.Skill Trident z 2400 Mhz DDR3
- Cooler : Corsair H80 with two Noctua NF-F12 (Another Very tight fit!)
- Psu : Silverstone SFX 450-G (Quiet but Dead now, replaced with a Silverstone SFX 600-G not quiet and that died too, now i have a Corsair RM550x that is very quiet)
- SSD : OCZ vertex 4 256Gb (Dead now, replaced with samsung 850 evo 1Tb)
Power Draw (Max load/Gaming) : 320w / 260w
Cpu temp were Awesome (less than 50° under heavy load) and stay realy quiet, GPU temp were not that good and it was not quiet at all (so i had to tuned the power Threshold down to 87%). The case was heavy (when filled) and too big (10.8 liters) to travel with. It was a very tight fit so it was painfull to add/remove component.

So i decided to replace my case with a Silverstone Milo ML07. It's a bit bigger (14 liters) but anyway i can't travel with sugo, and this little more room was welcome :)
I replaced the CPU cooler with a Noctua NH-L12 and a Gelid slim 12 uv. CPU temp went up but still good (less than 70° under load) and it's still quiet. GPU temp were good and it was not too noisy with power threshold set to 100%.
But i didn't noticed that SSD temps were High and my SSD died (SSD is right behind the GPU). Same thing happen to my motherboard. P8z77-I has a small riser card for VRM but in this case they can't stay cool.


Then i dediced to move this build into another case, the Lian Li Q25 and use it as a Multimedia/NAS/Casual Gaming PC connected to my TV. Build quality is far better than the silverstone. The case is a lot a bigger (20.4 liters) but i can fill it with 5 HDD and full gaming rig.
I replaced the CPU cooler with a Noctua NH-L9i. CPU temp are not that good (85° under load without oc) but it's quiet. GPU temp weren't good so i set again the power threshold to 87% to minimize noise. But HDD temp are realy good with a 140mm fan blowing directly on them.

Now i need a new gaming rig. So i start searching for a new case. I m realy impressed how thing change in so little time. First i found DAN A4-SFX, small but still too big for me (7 liters). Then the S4 mini, realy small (4.3 liters) but i don't want an external PSU. Then i found the Hutzy XS, realy small, internal standard PSU but the project died.
Finally i found the Custom_MOD Flex mini (mine is rev1 so 3.99 liters) and it seems to fit all my requirement.
Before i go further with this case, here the specs of the build i m planning to put in this little boy :

- CPU : Intel i7 8700k Delided and Silver IHS from der8auer team / Owned a bit pricey but it deserve it :D
- GPU : Gigabyte GeForce GTX 1080 Mini ITX / Owned Maybe i will replace it with Volta when it comes out
- MotherBoard : Asus ROG STRIX Z370-I GAMING / Owned No riser that can block heat, M2 slot in front of the motherboard and S/PDIF is all i want
- Ram : 32Gb (2x16Gb) Corsair LPX 4000 Mhz DDR4 / Owned @ 3466 15-15-15-35 1T BIOS 404 (I achieved 3800 18-19-19-39 2T With BIOS 426 but i prefer better latency)
- Cooler : Noctua NH-L9i / Owned
- Psu : FSP 500W Platinum Flex ATX / Owned, First i was waiting for the seasonic but it's coming in january and i don't want to wait that long
- SSD : Samsung 980 1Tb M2 / Not yet announced but samsung seems to follow a one year refresh rate and 960 evo is almost one year

And here some accessories i want to add for travel :
- Screen : Gechic 1101p / Owned
- Keyboard : Obins anne pro / Owned currently in ANSI layout but cannot wait for ISO
- Custom Keycap : Keycap white translucent in ANSI azerty (french) layout / Owned
- Mouse : Logitech G603 / Owned
- Tavel organizer : Inwagui travel luggage organizer / Owned
- BackPack : Osprey Farpoint 55 / Owned I love this modularity so i can put my travel organizer in the daypack or in the biggest backpack depending on my need

Some other accessories at home :
- Screen : Asus Rog swift PG35VQ / Not yet released
- Mouse : Logitech G403 / Released
- Mouse bungee : BenQ Zowie Camade / Owned
- Mouse pad : Steelseries QcK XXL / Owned
- Speaker : Mission LX-2 / Owned
- FDA : smsl ad18 / Owned

REVIEW and BUILD of FLEX mini rev1:

Specs :

Motherboard : Mini-ITX
Material : Full Aluminium
SSD/HDD : One 2.5" and M.2
Cooling system : No Fan but oversized vents on side and top panel
Expansion slot : One with two slot
Max Length GPU : 175mm (official, i measured a bit more so i think 175mm GPU will be easy fit)
Max Height CPU : 37mm with 3mm clearance (official, not yet tested)
Max Height RAM : 40mm (official, not yet tested)
Front I/O port : None (but you can ask for USB3.1 type C or USB 3.0)
Logo : None (But you got one in default)
Power Button : 12mm in front (rear default)
Filter : DustEND G1 removable (None default)
Accesories included : PCIe LiHeat 300mm D.type
Dimensions (official) : 100mm (W) x 220mm (H) x 181.5 (D) mm (3.99 liters)
Dimensions (measured) : 100mm (W) x 220mm (H) x 185 (D) mm (4.07 liters)
Weight : 771g
Color : Matte Black
Price : $174 (with option i choose)

Case i get don't have the dimensions it was supposed to have. I got no notification about it. But... I guess i prefer those dimensions, when i see that first batch of Custom_Mod MINI ITX can't fit GPU they are supposed to support.

Seller :

Contact with Sergiiua is realy good. He responds fast to any question and send advancement on production for each step. I asked him some modification from his default design and he did them exactly the way i wanted.
He is ukrainian, he use a translator so you should be realy specific if you want mod.
I sent my order on 8th june and paid the same day. First expected delivery date was 20th july if i remember well. Finaly my case was sent on 1st september and i get it on 9th september (From Ukraine to France).
So it took 3 mounths, i think it's quite good for something that is almost a prototype with modification to default design. And it seems the factory get some trouble with a bend machine so it took a bit more time.

Unpacking :

Case was sent in a tiny box, it travel by plane. Sticker says it's a gift, a commercial sample. I can't read the value. Anyway it passes through border without any trouble.

Case is well packed with some little polystyrene tiles on his side. I guess adding some more polystyrere couldn't hurt.

Outside :

First impression is awesome. This thing is tiny, cute and clean.

Front panel is very clean, only one power button and two little screw, some vent at the bottom.
But i see some improvoment that could be made :
- Hidding the two screw and put them near the vent.
- Adding some vent on the top for heat dissipation.
- Vent could have a nicer design, removing this large hole

Top panel is ok, i guess a little more vent could help.

Side panel are clean with tone of vents. The fit is good but not perfect. However one side panel is bent, as you can see from bottom.

Bottom panel is ok. You can see those tiny feet and four screw holes, two for PSU and two for SSD.

Rear panel is a bit disapointing. PSU screw holes and rivet have been made more than once. There is a second holes for a power button i guess. I think something is missing between Motherboard and PSU for a cleanier design.
And the most disapointing there is no custom number plate :'(

One word on painting, it seems good, i didn't see any scratch. I love this matte color, there is no fingerprint.

Inside :

First thing i noticed when taking side panel off is the screw seems not similar. The two on side are shorter.

On GPU side, you can see rear element are bended. GPU panel is bend too, no doubt. I think power button won't block PSU and 175mm GPU will be easy fit.

On Motherboard side, i think Pci-E riser is a bit too long. Power button wire is long enough to be plug anywhere.

Now from inside i understand why there is no more vent on top panel. I guess it's maximum you can have with current design.

Dust filter are all well applied except one on front panel.

Then i put all thing together again. The bended side panel was a bit harder to put on but it's ok. I was very cautious but some scratch appear near screw :/ I will see over time if other scratch appear when traveling with this case.

Bundle :

Bundle is minimal but it was expected :
- One Pci-e riser
- Some screw (PSU, motherboard and replacement)
- Zip ties for cable management
- One business card

I exepected at least some customization on this card like a "thx for support" but no :(

Assembly :

First element i get is my PSU. I try to put it in, maybe i will have to remove it later when i get other part.

Finally i get the 500w flex platinum PSU from FSP, i didn't wait for the seasonic (someone from overtek says it's incoming in january).
This thing is so tiny ! And heavy compared to it's size !
This PSU doesn't have 8 pin Pci-E but two 8 pin 12v EPS so i ordered one adapter from EPS to Pci-E.

As expected it was an easy fit. Front power button wasn't a problem at all. But rear panel was a bit more disapointing. Only one screw fits ! I had to bend the panel to fit a second one and there is no hole for the third one obviously. However two screw seems enough, the PSU in not moving at all.

Cable management will be a hard time :D I think i will have to remove some of these useless hard drive power cable :D

First thing i get after PSU, is my 8700k ultra edition. So i did some test outside of the case and some tuning for best compromise performance/Heat/Noise. I will talk about it a bit later.

Finally my gigabyte 1080 mini arrived. Let's put everything together !

When i was thinking graphics card will be easy fit i was wrong. It didn't fit at all at first attempt. I had to take off the rear PCi bracket. I installed the bracket first then i was able to put the graphics card in the case by bending a little bit the case. And finally it fits ! But i think something a little bit bigger won't, like an MSI 1070 GTx Aero. So 185mm long is realy the minimum you can use for and 170mm long card.

Ok so then i was able to mount everything without too much trouble. Here is the result :

However I had to do three modification from stock element.

First, my PSU got too much wire, so i removed every useless Sata wire. It fits without any modifcation if you don't want to remove them.

Second modification : when i plug the power cable in my PSU, i noticed that the PSU is moving, two screw are not enough. So i added a small piece of steel in front of my PSU and screw it from behind.

Third modification : Do you remember my crappy rear panel ? A friend of me 3D printed a little piece of plastic and finally this rear panel is acceptable now :

Last edited:


Average Stuffer
Original poster
Jun 8, 2017
Tuning/Temp/Noise :

CPU (8700k ultra) :

So i did some test, undervolting and overclocking to find the best configuration. I use Prime95 with Small FFT, AVX Enabled, AVX offset Auto, it's the worst case scenario.

For each test :
open air (Room temp 21°c)
FAN Speed auto (Standard Fan curve)
Integrated GPU

Test 1 (Idle @Stock + Ram OC):
Asus Power enhancement Off
Asus cache Auto Overclock Off
AVX Offset : 0

Test 2 (Load @Stock + Ram OC):
Asus Power enhancement Off
Asus cache Auto Overclock Off
AVX Offset : 0

Test 3 (Load @Stock = BIOS default settings):
Asus Power enhancement On
Asus cache Auto Overclock On
AVX Offset : 0

Test 4 (Load @Stock Undervolt):
Asus Power enhancement On
Asus cache Auto Overclock On
AVX Offset : 0

Test 5 (Load Oc 4.7 all core):
Asus Power enhancement On
Asus cache Auto Overclock On
AVX Offset : 2

Test 6 (Load @Stock Undervolt + Ram OC):
Asus Power enhancement On
Asus cache Auto Overclock On
AVX Offset : 0

I have a review with a not customized 8700k and same stress test but far better cooler.
It's in french so i added his result to my table, this way you can compare.

His configuration :
CPU : 8700k
Mobo : Asus ROG Maximus X Hero
Cooler : Noctua NH-D15 and NZXT Kraken X62
Ram : 2 x Crucial Ballistix DDR4 8 Go 2400 MHz
PSU : Seasonic Snow Silent 750
GPU : Asus ROG GTX 1080 Ti Poseidon Platinum

Result :

Screenshot :

I plan to use case 6 (maybe with small AVX offset) in my case as Prime 95 Small FFT is a worst case scenario.
For those that are interested by a 8700k in SFF case, you cannot expect using it without delidding and undervolting.
Maybe even underclocking if you don't want to delidd.

About Result compared to the reviewer. With same BIOS configuration (my Test 2), we achieve same power consumption on CPU (My idle is 21w below and almost same for load with 19w below) and my CPU is only 6°C higher despite the fact that i use a far smaller cooler.

Motherboard (Asus ROG strix Z370-I Gaming) :

My stick are advertised for 4000Mhz CL19 but it always fail to boot. So i decided to find the best combination of BIOS and memory timing.

BIOS 404:
3466 15-15-15-35 1T (According to AIDA : 49671Mb/s read, 45ns latency)
Can't get higher than 3466 even with high timing
XMP profile not working
3866 working with only one stick of ram

BIOS 426:
3200 13-13-13-33 1T
3466 15-15-15-35 2T
3700 16-16-16-36 2T
3800 18-19-19-39 2T (According to AIDA : 51940Mb/s read, 49.3ns latency)
Can't get higher than 3800 even with high timing
XMP profile not working

So i decided to go back to 404. Not only for ram, my 8700k frequency are better under full AVX load.
And i choose better latency over a small amount of bandwith.

Some more words about this motherboard. Someone ask me about this video :

He is true, i don't know why but it seems Asus choose to use very High and aggressive voltage (and other reviewer state the same for other Asus Mainboard) and for LLC (load line calibration) it's true too. But i don't care about LLC as i m using offset vcore for tuning and undervolting at stock frequency. It just take a bit more time to find the best configuration. LLC is used when you start overclocking with static vcore.
He is also true about XMP profile,if you use it, it's even worse, some Auto-Overclock is set on and voltage take a huge +0.100V increment by default.
It seems they change a little bit this with 426 (wich came out the 10/20 and you video is 10/13) but i don't like it.

I don't like it because, Ok voltage came down but frequency at Load came down too sometimes by a huge margin.
Under Prime95 Small FFT (worst case scenario) with 404 BIOS i can maintain 4.3Ghz (Max frequency on all core) with some tuning on vcore. But with 426 and same tuning i only achieve 3.9-4.0Ghz at load with almost same power consumption.

I also noticed a vcore peak at start where frequency start at 4.3Ghz during 7 second but power consumption was higher too by a good margin. Maybe it means LLC is working, i didn't check much.

So for those reason i choose the 404 BIOS,if you tune it, it's far better than 426.

Graphics Card (GTX 1080 Mini) :

I use Heaven Benchmark for load (1080p ultra, high tesselation, AA 4x)
I used standard FAN curve.

Without Panel on :

OC :
GPU : 1911Mhz @0.863V
MEM : 5500 Mhz
Temp : 75°C
Result : 162 FPS
Power Consumption (from wall): 216W

Undervolt :
GPU : 1782Mhz @0.800V
MEM : 5500 Mhz
Temp : 72°C
Result : 146 FPS
Power Consumption (from wall): 196W

With Panel on :

OC :
GPU : 1911Mhz @0.863V
MEM : 5500 Mhz
Temp : 80°C
Result : 162 FPS
Power Consumption (from wall) : 216W

Undervolt :
GPU : 1782Mhz @0.800V
MEM : 5500 Mhz
Temp : 77°C
Result : 146 FPS
Power Consumption (from wall) : 196W

During the worst case scenario (OC with Panel on) the noise was acceptable. I can't hear it when i m playing. Idle it's dead silent.

I think these temp could be better. The front panel is very hot during test, i think some small vent will help a lot to cool it.

One more concern i have is SSD temp, they get pretty high during test of the graphic card, sometimes it get as high as 50°C. I think it will be better with a M2 SSD.

Performance / Gaming :

Some early test of CPU and RAM


Traveling :


Conclusion :
I m impressed by this little case, it's exactly what i m looking for, a small well vented case that can fit a full build like far bigger case.
About build quality, it's awesome if you know what you buy : a prototype. I was able to overcome to every problem i get, sometimes with small modification. However i was disapointed by bad alignement for some screw and poor quality of my rear panel.

Design could be improve too, i think some vents in front of the case would help a lot to cool down the GPU.

If you want to use an insane configuration (8700k, GTX 1080) you should choose wisely your component and be prepared to tune during long hours.
I think a more acceptable and easier configuration is an intel i5 8400 or ryzen 5 1600 with a GTX 1060.

Even if you can fit a 2.5" SSD, i think this shouldn't be consider has temp can go very high when GPU is load. And i think it will be even worse if the SSD is in the front of the case.

I do not recommend using filter, they retain heat too much.

To conclude it's a good case, that could be improve. I won't recommend it if you want something perfect. I will wait and see if build quality improve. I m also ready to pay more for a premium finish.

Pro :
- Tiny
- Tone of vents
- Build quality (prototype)
- Seller
- Customization
- Removable dust filter
- Standard ITX, PSU, GPU and CPU cooler
- Can fit One SSD
- Clean Design
- Price (Considering Customization and Dollar/Euro parity)

Cons :
- Build quality (industrial case)
- Screw alignement
- Advertised GPU that won't fit (MSI 1070 GTX Aero)
- Useless dust Filter (retain too much heat)
- Useless SSD slot (Run too hot to be use, could be worse in front)
- Design could be improve (Vent in front of the case for GPU cooling)
- Some scratch appear near screw. Should be cautious when traveling with this case.
- Delivery time (3 mounths but maybe less now)
- Ram compatibility (Only concern rev 1)
- No custom number plate (Like FLEX #001)
- Can't add fan or anything else
- Not final design (Improvement can be made)
- Case i get don't have the dimensions of the case i ordered
Last edited:

CC Ricers

Shrink Ray Wielder
Bronze Supporter
Nov 1, 2015
Seems like the quality is hit or miss with these cases, from the pictures I've seen.


King of Cable Management
Jan 19, 2017
you know, I've never seen any issues out of any of the slims or minis its literally the newer designs that I've seen issues out of had some issues with like panel length in batch 4 of the minis but nothing like this


Average Stuffer
Original poster
Jun 8, 2017
I added some pictures of inside.

It's true build quality could be far better with small improvement. But it's almost a prototype, so i don't mind too much. If quality improve i may order an other one and give this one to my father :D


Airflow Optimizer
Feb 26, 2017
Prototype or not, that rear panel is FUCKED UP! I know this case is cheap compared to the Dan A4, but it's not that different than an M1 or a Lian Li. Really disappointing to see such poor build quality on a case this expensive. That being said, I'm happy that you are happy with the case and I hope you can get your entire set up together. It sounds like it'll be amazing!


Average Stuffer
Original poster
Jun 8, 2017
Today i am looking for a backpack for travelling with my gear. So i measure my case to be sure. And i m quite surprised. The case i got don't have the dimensions he was supposed to have when i ordered it. It's a little bit longer : 185mm (official : 181.5mm). I didn't get any notification of this change.

However i m not disapointed at all because a lot of people seems to have hard time trying to fit their GPU inside their Custom_MOD Mini ITX.

Finally i found exactly what i was looking for. A luggage organizer that fits perfectly all my gear (case, screen, keyboard, mouse and cables) and waterproof :

I think i will use it with this backpack
Last edited:


Average Stuffer
Original poster
Jun 8, 2017
I thought of buying this case but thanks to your pictures I am glad that I didn't buy it.

I understand, design is good but quality is disapointing. I still hope some improvement on this side for a second case. Mine is from first batch, maybe next batch will be better.

And until i put everyting together i can't recommend this case.

I ordered my PSU so i will add some picture soon. Finally i will skip waiting for the seasonic (it's incoming in january) and going with the FSP 500w platinum. I will add this adapter as there is two eps12V and no 8 pin pci-e on this psu.

The main drawback for this PSU is the lack of -12V rail, it may prevent some motherboard to POST. But someone from overtek ensure me that they have a solution if it happens.

1. -12v. Not a problem we have a solution if needed.
2. Adapters, stock just awaiting customs clearance. Hopefully in next week.
3. We do have more 500W units available.


Average Stuffer
Original poster
Jun 8, 2017
Just a small update.

I ordered my 8700k ultra edition, asus Z370i motherboard and still waiting for an available 1080gtx mini :D

I get my new Keyboard, the Anne pro. It only exist in ANSI qwerty however i m french so i need my Azerty layout :D I just get my custom Keycap too from MaxKeyboard, and they did a great job.

As you can see my old keyboard looks ugly in comparison :D
It's expensive but i didn't had any alternative and i truly like the result


Average Stuffer
Original poster
Jun 8, 2017
Finally i get everything (except the M2 SSD but i guess samsung will release soon the 980). I finished the assembly part, and modification i had to do. I added some about tuning, temp and noise i achieve.

I will add more about gaming performance and traveling soon. I already travel once with my case and all my accessories in a small backpack. I m very please of the result :D
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Airflow Optimizer
Apr 16, 2017
Hey, is there any update about the psu you use? I would like to build a similar pc with i5-8400, m.2 drive and gtx 1080 itx. Do you think 400w flex atx %90+ psu will handle them?


Average Stuffer
Original poster
Jun 8, 2017
My PSU is still working great. After month using it i can say it's a very good one, quiet silent when gaming (200w power draw) but start to be annoying under full load (300w power draw) or during very long gaming sessions.

I use a 8700k and gtx 1080 itx, both undervolted with small OC. My max power draw is around 300w from wall so a 400w PSU should be enough. But i think a 400w Flex ATX will be very loud under full load.

If you plan to use a GTX 1080 itx with a custom_mod flex mini, you should take the front vent option. My case got no front vent and during long gaming sessions the case is heating a lot and start throttle.
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Trash Compacter
Jan 29, 2018

Could you elaborate more on the noise from this 1u/flex FSP power supply unit? I am interested in getting one for an upcoming build, but I am a little concerned about the noise.

So under moderate load it is quite silent? How is this comparable in noise to the noctua L9i HSF you have as scale?

Under 40-50% load is it reasonable? Or is it clearly the loudest component in the system and starting to sound like a hairdryer?



Airflow Optimizer
Apr 16, 2017
I'm going to 3D print the case and yes it will have gpu vents on the front side. For the psu, I may get a modular flex atx psu from Geeek. It's a Delta DPS-400AB 400W actually.


Average Stuffer
Original poster
Jun 8, 2017

Could you elaborate more on the noise from this 1u/flex FSP power supply unit? I am interested in getting one for an upcoming build, but I am a little concerned about the noise.

So under moderate load it is quite silent? How is this comparable in noise to the noctua L9i HSF you have as scale?

Under 40-50% load is it reasonable? Or is it clearly the loudest component in the system and starting to sound like a hairdryer?


Boot : 0-100w (0-20% load) :
Psu : VERYYYYY noisy, like an hairdryer during 15sec
Noisest part : PSU for sure

Idle 0-60w (0%-12% load) :
Psu : dead silent
Noisiest part : I don't know, CPU cooler i guess

Light CPU Load 60-100w (12%-20% load) :
Psu : silent
Noisiest part : CPU cooler

Heavy CPU load 100-150w (20-30% load) :
Psu : quiet silent
Noisiest part : CPU cooler

Light gaming 150w-200w (30%-40% load) :
Psu : I can hear it but it's ok for me (still less noisy than my NH-L9i set to 100%)
Noisiest part : PSU

Heavy gaming 200-250w (40-50% load) :
Psu : Start to be annoying for me, specially during long gaming sessions when the case is hot (Noisier than my NH-L9i set to 100% but less than my GPU fan set to 100%)
Noisiest part : PSU

Burn 300w (60% load):
Psu : noisy, more than my GPU with fan at 100%
Noisiest part : PSU by a huge margin