The following links should help.

https://www.dell.com/community/Desktops-General-Read-Only/Dell-T3500-Upgrading-FAQ/td-p/5151130

https://www.youtube.com/watch?v=-ZaXjJTfZls

And the PSU that was installed in the video.

https://www.amazon.com/gp/product/B018JYHBE6/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B018JYHBE6&linkCode=as2&tag=greenpcgamers-20&linkId=e208f8f59748ade28d6a788a57b7dffb

no reason given

for GPU card that uses 250 to 350 watts, they need 2 PCI-e AUX power cables

so we buy PSU that has those.  I cant see in side your PC, and know what you have not or what is planned or what PCI cards you might install or how many HDD loaded there, (all things matter inside, tell that first)

what do you have now is the 1st question .

the where do you want go....  upgrades, all in the futures, are addressed now, not told.

gaming?

EVGA 700BR 100-BR-0700-K1 fits and works fine.

EVGA 700B1 also fits and works fine.

B2 B3 BQ G2 W1 N1 versions from the SAME VENDOR Do not work correctly.

https://www.bestbuy.com/site/evga-700w-atx12v-eps12v-80-plus-bronze-power-supply-dc-dc-technology-black/6346160.p?skuId=6346160

https://www.evga.com/products/product.aspx?pn=100-BR-0700-K1

• I just wanted to add that I’d suggest going on YouTube. I couldn’t believe how many videos I found of people upgrading the T3500.

• The stock psu should have the connections you need. I found mine simply zip tied to other cables.

Are you sure that they will be zip tied because I bought a 80mm fan to cool my heatsink but dont know where I can connect it with the psu. Do you know which cable is used for that?

@igdeb 

@TheJetrug 

@Semi-geek 

@JOcean 

Dell fan headers for this model are not standard. You will need molex to fan header.

Molex to fan adapter  

https://www.youtube.com/watch?v=jplz8H58lmU

Dell T3500 Upgrading 5151130

What's the reason other power supplies from EVGA won't work. I'm looking at the 750 g5

 The Dell T 3500 is a BTX system. It has roots in LGA775 Netburst CPUs. +5V. power was used back then. You need a PSU with enough +5V. power to work in the T3500. Some of the EVGA have this. Some newer one may not. I've run the EVGA 850B2 in a Dell. This old architecture also show up in video card compatibility issues with newer AMD GPUs.

@William P​  (ik this thread is over 5 years old but still) whats the minimum amount of +5v power the t3500 needs yo work?