can i upgrade psu optiplex 760

You can upgrade the PSU and this forum page has far more information for you.

can i put thermaltake smart 430w or no?

yes, i have an MT, i want put a gtx 650 low profile and a q9400

If 760 MT, yes np.

if 760 DT or SFF, no.  DT/SFF board use mini 24 pin, not standard form factor psu.

It looks like a go, but is there a certain GPU you want to power?  I take it you have an MT (mini tower).

Re: i want put a gtx 650 low profile and a q9400

not all 760 MT board support quad core 2 cpu.  before you invest on gpu first confirm your motherboard DP/N can support quad.

The T674K only supports dual core CPU's where as the U562N will support quad core CPU's.

quote: 

T674K motherboard does not support Core 2 Quad CPUs, only Core 2 Duo CPUs.

U562N motherboards support both Core 2 Quad and Core 2 Duo CPUs.

I need a memory refresher.  Is the 780 like that too or just the 760?

Better double check if the mini tower can use a gpu with low profile bracket. I thought most tower models have full size slots.

The GTX 650 is only 65w, so you're good there.

In case it comes up in discussion, as it has others the Thermal take 430w PSU has more power on the 3.3v/5v rails than the stock PSU, which is also good.

only Dell engineering data on 780 MT motherboard P/N can elucidate this.

what is known is C27VV board supports quad core.

Thanks.  Thought I had it in my archives, nope, just the SFF.

No for 2 reasons

1 the Thermaltake supply doesn't work

2 the 760 uses non standard 24 pin connector.

Bare miniumum is EVGA EVGA-100-BR-0500-K1  with Moddiy Adapter

and thats only for mini tower,. Smaller units wont fit inside the case.

https://www.amazon.com/EVGA-100-BR-0500-K1-Bronze-Power-Supply/dp/B07DTMXD83

https://www.moddiy.com/products/Dell-980-960-780-760-PSU-24-Pin-to-Mini-24-Pin-Adapter-Cable-10cm.html

@redxps630 

Yes there is a problem because it uses a non standard 24 pin connector for ALL sizes.  MT included.

I'm in agreement with @redxps630 .  It's the 760 DT, SFF, & USFF that has mini 24-pin connector.  I did point this out before.

However, all sizes of the 780, including MT, have the mini 24-pin.