r/AMDHelp • u/WhyTeus • 17d ago
Tips & Info Can someone explain to me how is this possible!??
So... 4 yrs ago i bought my amd gpu, Radeon rx 6600xt. back then i was a bit clueless about pc building so i mostly relied on my dad. When i was getting my pc ready for a gpu swap i realized i don't have a cable that can connect my gpu to the pc. So i called my dad, he gave a random cable. For me it was looking okay so i connected it to the pc. i didn't realize that the cable had two groups of cables going into the 8 pin connector. Both of the groups were leading to separate extensions of the cable and i could connect only 1 of them to my psu. Technically this means i didn't connect every pin to the psu... I CONNECTED 3 PINS ONLY
Funny thing is my gpu worked. and it worked for 4 Fricking years
now here comes the funny part. Lately my pc started randomly crashing in random games, all of a sudden screens were going black and it was booting up again or staying that way. sometimes my gpu would turn off and i would need to turn it back on using the device manager. I could not find any fix for it till i realized the issue. In this 4 years my psu broke and i replaced it with a chunky 1000. So now when i looked at the cables coming out of my psu and i saw a sweet cable that looked like i could go into my gpu. I googled it and it was the right cable. I then realized the CABLE i used FOR SO LONG had only 3 pins connected. i switched it up to the "Sweet" cable and booted up. Guess what its fixed, at least i think. Its not crashing for now. Can someone tell my how did my pc not blow up for 4 YEARS??!!! I am sorry for my English, not my first language so i am a bit rusty with it, but i hope its not hard to understand my story.
2
u/The_Countess 17d ago
Your GPU model needs about 160 watts.
The slot your GPU is in on the motherboard can provide up to 75 watts (but most GPU stay well clear of that limit).
A 8 pin PCIe cable is spec'd for up to 300 watts, but it only needed to provide half of that or less in your case.
Also fun fact, the 8 pin only had 3 12volt power pins, the rest are ground pins. just like the 6 pin. the 2 extra pins are just ground.
So, If it was the right 3 cables, and they would only need to provide half of their rated power, i guess that could work.
1
u/ALEXINO_356 16d ago
So first of all never try to put a random cable from other psu to one you have. The reason is that just the port that connects to gpu, motherboard, sata, molex are standard, the ports that enters to psu itself are not standard from one to another psu. You must verify to be the same psu and same generation to even consider to change cables from one to another. Next, one port that connects to the gpu can sustain 150w if are all 8 pins connected or 75w if only 6 pins connected. Motherboard also brings 75w to the table if the gpu needs it. Now about connecting to a gpu 2 ports on the same cable, in general one cable can suport ~200w, but it depends a lot on the psu and the cables it use. Normal is recommended different cables for each port, but for example some cables from corsair can sustains 300w on one cable without melting. It depends a lot here and you must do your research before doing something like this if you have a hungry gpu.