XPS 8930, upgrade compatibility?

You can install an i7 of the same (8th) generation, and maybe the 9th but nothing newer.

The video card is standard and assuming you look for  a moderate upgrade, should be doable.  A high end upgrade likely would require a replacement power supply.

Also beware that Microsoft upped the CPU floor for Windows 11 to the 11th gen with the 24H2 release, so it may not be long before an 8th or 9th gen CPU is abandoned by coming updates to Windows 11.  That may tip the balance toward a new system rather than upgrading this one.

So you have an XPS8930 it seems by the model of the motherboard.

Win11 does need more resources than Win10 did. However, an Intel i5 CPU isn't the fastest either.

One thing that might help, more RAM, you didn't specify how much you had though.

Also depending what to want to do, a better video card.

If you need to buy extra RAM (assume you have 16GB's) and a more powerful video card (for game play) you'll be looking at possibly $500 USD. If you do have 16GB's, you could try adding another 16GB's, but that doesn't always work as well as getting 2 16GB's RAM sticks and installing them.

A better video card might require a new PSU and some extra cooling as well.

Upgrading the CPU, they are tied to the CHIPSET installed. Normally a CPU would require a new Motherboard... added expense.

Consider putting any new money spent as if applied to a new PC, it might be better doing that.

Your 8930 it seems has a Z370 chipset, and these possibly will fit/work in it, https://www.cpu-upgrade.com/mb-Intel_(chipsets)/Z370.html , however, they may NOT as a BIOS update also might be required?

Dell did sell some 8930's with 9th Gen Intel CPU's (See https://www.dell.com/community/en/conversations/xps-desktops/faq-xps-8930/647f78fdf4ccf8a8de7152b3) but it probably required a different, later model, motherboard.

For best performance, you can upgrade the processor to an i9-9900K.  It will require voltage regulator heatsink and premium CPU cooler.

For matching graphics card, you may consider RTX 4070 Ti.  If your system was not shipped with 850w power supply, you can upgrade with standard ATX power supply.  Preferably modular for better cable management and with 150 mm depth as OEM mounting cage size.

Review this benchmark site for some ideas from other systems performances in correlation to their processors and graphics cards  https://www.userbenchmark.com/System/Dell-XPS-8930/70003

agree w chino on the top high end cpu upgrade.  only concern is the cost of 9900k may far outweigh benefit of a more practical upgrade from i5 to i7-8700  which is around 100 or less, or even i7-9700k.  in 2025 spending 200+ on older gen cpu upgrade is not great compared to getting a newer Dell model (even if used) such as Optiplex than can be so much faster than coffee lake refresh.

Re: starting to show it's age when processing certain materials (especially after upgrading to Windows 11). 

use task manager to eval whether you are using cpu or gpu towards 100%.  in my experience the Win 11 frequent update heavily tasks cpu, and can often drive older cpu towards 100%.  if so, cpu upgrade is worth a shot.  if for gaming improvement, totally different story.

XPS 8930