HP T740 thin client with Radeon RX 6400 GPU


New Member
Jun 3, 2020
I got a good deal on a HP T740 thin client, and decided to build it as my travel PC, I bought a Radeon RX 6400 GPU, it fits perfectly, but upon connection of the power cable, I get 3 red light beeps and 4 white light beeps, that according to the documentation:

The red light blinks three times, and then four, short white light blinks (3 long red, 4 short white)
This condition indicates a potential power system failure.
  1. Reduce to minimum configuration (CPU, System board, PSU, 1 DIMM of memory), and then isolate the failed component.
  2. Reduce further if issue persists.
  3. Test your system with a known good PSU.

it looks like that GPU card is pulling to much power I guess and there is a system check that prevents it to even booting up with the card installed

with out the card it works great, Windows 10, 1TB NVME and 32GB RAM at 3200 Mhz

is there I BIOS setting or something similar that would let me disabled this check in order to at least boot up?

I feel that the Thin client should be able to handle it, but I could be wrong



Jul 13, 2018
HP's "QuickSpecs" for the t740 mentions the AMD Radeon E9173 as a GPU option. AMD's specs for that GPU show a power draw of 35W. I doubt the t740 could support any GPU with a significantly higher power draw (guessing 40-50W max) based on the 90W power adapter. To be clear though, I've never tried any GPU in my t740.

Good luck with your troubleshooting/research,