Studio XPS 435T/9000, PSU Corsair HX750

Yeah, the OEM power supply is 140mm depth and you are installing 170mm one.  If depressing the sheet metal cable holder down far enough, it might fit.  Otherwise, exchange for PSU with 140mm to 150mm for a drop-in fitment.  Example, Corsair RM750e (either 2023 or 2025 version).

The Corsair HX750 fits well; it's just narrower than the original PSU. Since I'm on a tight budget, I picked this one up from someone on Facebook Marketplace. It's secured with two screws and seems stable for now. I'm not sure how it'll handle vibrations over time, but it's surprisingly quiet, which is a huge relief compared to the original PSU that had a high-pitched whine that was there even when the computer was off, driving me up the wall. The Corsair has no such noise. Do you think the Corsair RM750e (2023) will fit nicely? I'm considering getting it with my next paycheck and saving the HX750 for another build. Thank you for your help. I was hoping there might be some sort of bracket to help with the installation.

For the performance value of the 435T, do not invest too much into it.  Although, the RM750e will fit nicely.

Re: it's just narrower than the original PSU

the original psu is not ATX form factor as you alluded to.  It is taller

when installing standard ATX psu they would fit the psu mounting holes, but there will be a gap of empty space or air beneath the psu, which is only cosmetic.

Hmm!  Did not own one but done research with YT video for PSU upgrade and verified solution at this thread indicated XPS 435t uses standard ATX power supply  https://www.dell.com/community/en/conversations/xps-desktops/studio-xps-435mt-i-need-to-know-what-size-psu-to-buy-mine-died/647fa31ff4ccf8a8de8e086c

I did not know it uses nonstandard form factor psu until I picked up a second unit and tried to upgrade psu.

a standard psu can mount properly in the 435T case rear mounting holes which follow the standard spacing, but the chassis rear psu window is taller than standard atx psu, which leaves an empty gap at bottom of opening like a window incompletely shut, a bit odd and unseemly but not big deal.

quote 435T oem psu Dimensions: 150mm x 98mm x 160mm

standard ATX psu A standard ATX PSU is 150mm x 86mm x 140mm,

therefore the oem psu is 12 mm taller.

oem psu

standard psu

@KidMiracleman​ , I had to replace the PSU on my XPS 435T/9000 and had the same experience - the original PSU is a non-standard size.  I have both an air gap at the back of the PC below the PSU of about 3/8 inch and only 2 of the original 4 screw holes line up with the new EVGA 600 GD PSU that I put in.  Works fine.

Two Dell PCs often get confused:  the full size red and white tower XPS 435T/9000 and the black mini tower XPS 435MT (I assume MT stands for Mini Tower).  I also have a 435MT in the house that I've replaced the PSU in and it had no fit issues - standard size PSU.

@Techgee​ Interesting.  Thank you.