[SOLVED] Optiplex 7020 MT GPU and PSU, Definitive

[fitsum]

Hey Guys,

Office PCs are getting popular, as i found out while choosing my title. Got the stated PC from 2015 on office clearance sale for cheap. wanted to see my upgrade path, did some research, from the dell website and/or well here. I didn't exactly wanted to play it safe and spend a lot. While longevity and safety is important, I wanted to know why certain choices are made. here is my spec and i have a bunch of questions that i want to get under one thread. i believe this is one of the most powerful office PC specs for the time and yeah...this MT has more proprietary mobo power layout.

Dell OptiPlex 7020 MT

manufacture year -> 2015
processor-> Intel Core I7 4790 @3.6-4.0Ghz
memory-> 4x4GB DDR3-1600
storage->Seagate 500GB 7200rpm SATA
optical drive-> DVD+-RW
PSU-> max 290W 80+Bronze Stock

Questions (just wanted all the basic questions here, bear with me for the ignorance)

1. I see total system consumption graphs on GPU reviews and they state some as low as 185-200W on 8700K processors for 1650s or similar GPUs under load. but the GPUs state a 300W power supply requirement. Why is that?
2. There are 2 ways this will go now....

2.1 Can I use the stock PSU with an adapter cable to power a 75W GPU or similar?
2.2 Do I need an external PSU with the traditional 6-8 pins to power just the GPU?
2.2.1 Which GPUs wont bottleneck the CPU?

PSU spec:

MODEL: AC290EM-01
DC OUTPUT:
+12.0VA --- 14.0A
+12.0VB --- 16.0A
+12.0VSB --- 1.67A
TOTAL POWER 290W MAX.

Pic for the mobo layout

Thanks...

 

[Gerald6049]

I see total system consumption graphs on GPU reviews and they state some as low as 185-200W on 8700K processors for 1650s or similar GPUs under load. but the GPUs state a 300W power supply requirement. Why is that?

The Recommended PSU requirement value is for the whole system, not only for the graphics card/s.

2.1 Can I use the stock PSU with an adapter cable to power a 75W GPU or similar?

You can. it will run, but really not recommended using stock/built up psu for gaming purpose.

2.2 Do I need an external PSU with the traditional 6-8 pins to power just the GPU?

Rather than use external PSU just for GPU, why don't use a good PSU for the whole system ?

2.2.1 Which GPUs wont bottleneck the CPU?

IMO GTX 1060 or RX 580 still good, 1650S wouldn't be bad.