A4 SFX to the max - 3900X, RX5700XT, Asetek 645LT, alot of trouble - it works, but isn't recommended!


Cable Smoosher
Original poster
Apr 20, 2018
Specs and setup:
  • Dan A4 SFX V4.0/3.0 hybrid
    • 4.0 base frame; side panels / 3.0 front panel, USB Port /4.0 Riser
  • Asetek 645LT with Noctua A9x14 HS
    • high RPM L9i Version
    • Arctic MX4
    • Corsair AM4 mounting bracket
  • Ryzen 3900X
    • PBO disabled, stock TDP
  • Powercolor RX5700XT Red Dragon
    • 0.5mm washer mod
    • modded to 2x Noctua A12x15 as exhaust
    • Arctic MX-4
  • Asus B450-i Strix Gaming
  • Corsair SF600 Platinum
  • 32gb Crucial Ballistix LT 3200mhz
  • PNY Xlr8 2TB SSD

It took 4 attemps to get this thing working; Changelog of failed attemps in spoiler so no one gets confused:

  1. RX5700 reference with blower, Noctua L9i with AM4 mounting and shroud; bottom Fans as exhaust; no mods; SSD underneath MB
    • CPU and GPU throttled heavily
    • SSD idling @ 70° under gpu load
    • System is not usable due to occasional slowdowns, bad performance
  2. changed to Powercolor 5700XT Red Dragon; Asetek 645 LT standard A9 Fan as Pull; Case fan as exhaust
    • Case fan is VERY loud (too close to Motherboard)
    • MB VRM temp @ 85+°C
    • GPU tjunction @ 105°
    • CPU still throttling (not as badly ~3500mhz)
    • you can burn your fingers when touching the case (CPU takes 60W extra with 645LT; GPU not throttling and without exhaust from blower) while stressing both CPU and GPU
  3. Case Fan changed to intake; modded GPU to A12x15 as intake; 0.25mm GPU washer mod; SSD moved to front
    • GPU temps slightly improved
    • MB VRM @75°c
    • SSD idle @ 40°C
    • rest showed no improvement

Final Setup:
  • Asetek 645LT changed to A9x14 HS fan (intake)
    • no more throttling
  • Modded GPU further (0.5mm washers)
    • reduced GPU-TJunction delta to 10-15°C under load, 0° @ idle
  • GPU Fans changed to pull (exhaust); Controlled by GPU (Adapter)
    • this heavily improved both Case temperature; GPU Temperature
    • slightly more noise, from gpu, but still less than 645LT
    • no more burnt fingers, case hotspot moved to PSU exhaust (!)
  • removed bottom Fan grills, added 92mm wire fan grill
    • further improvement on CPU and MB temps; reduces noise from Case Fan by 75%
  • This setup is very quiet @ idle, but fans will spin to 100% (as loud as your average Notebook) under load

All temps were taken after 10 mins of stress testing, Ambient @ 23°C, but they will not increase anymore (645LT has a small amount of liquid and reaches its final temp very quickly)

Stress Test: simultaneous 10 minute Cinebench R20 loop; 10 minute MSI kombustor @0% Powertune

Please forgive my low quality Pictures, i will update these once I take it apart - the build process took me 20 hours with all revsisions and i was in a bad mood... (now waiting for my Ncase M1, Dan A4 will move to my HTPC build)

Some final A4 SFX recommendations:
  • DON'T use a 3900X (or 3950x) in this case (or any 105W CPU) if you don't have an AC unit - it will work at 20-26°C ambients but will throttle above that
    • changing cTDP hurts performance by ALOT (65W = slower than 3700X except for highly threaded workloads)
    • it is possible to run it without throttling, but requires some extra attention
  • get the SF600 Gold if you plan on using 645LT with stock PSU cables.
    • It has thinner unsleeved cables which stay together as a ribbon and can be seperated when reuiqred.
    • sleeved stock platinum cables may block the GPU form seating properly and are a PITA to route
    • its fan starts earlier which helps case temps
  • Don't buy a board with a backside M.2 slot if you plan on using a mid-high end GPU
    • the MB tray heats up and will toast your SSD
  • 645LT:
    • get the SF600 Gold PSU with it - it has thinner cables
    • buy A9 Cromax or use a Fan coming from an L9 - they have higher RPM than normal A9 (~2500 vs 2000)
    • stick to 65W CPUs if you dont plan to mod your GPU Fans (heat will build up in your case)
    • the mounting screws are prone to breaking, be gentle!
    • you might have to reseat it several times for optimal performance - burn in for an hour after every reseat before evaluating; my final mount was the worst after 5 mins, but the best after 1 hour
  • GPU: change your fans to noctuas and run them as exhaust - it reduces Case temps considerably and helps the 645LT

My verdict: The case is nice and it's impressive that you can get this hardware running properly; but it takes alot of work and attention to do so.

Personally i'm going to switch to Ncase M1 V6.1 as it has a lot of advantages for high performance systems and still fits into my backpack.


Caliper Novice
Mar 2, 2020
You should look into doing the Losercard Mod for the Dan A4 with the 3900x.

Also read this post below in regards to checking temps and maintaining performance on a 3950x. I would assume this would work with the 3900x as well. I have nothing for your GPU temp issues. I believe in general the 5700xt's have been noted as running very hot? I wouldnt run one knowing this in this case.

Losercard Mod for Dan A4.

3950x Eco mode + PBO analysis for temps and power usage. Might be a good option as well to lower your temps.
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