XPS 8300, slow performance, upgrade needed?

And to answer your other question, go to the Microsoft site and follow their instructions to create a bootable USB stick (at least 16 GB) with the latest version of Win 10 on it.

Plug the USB stick into the PC before you power on. Then power on, immediately tap F12 and look for option to boot from USB. Follow the instructions to do the clean install.

You'll need to back up all your personal files on external media, before doing the clean install. And you'll need to know your Win 7 product key and have installation media and product keys for all apps (eg MS Office) you will have to install.

If this issue started after you upgraded to Win 10, it could be a problem with the OS upgrade. Did you do a clean install of Win 10 or install it 'on top' of Win 7? And that might require you to wipe the hard drive and do a clean install of Win 10 and all your apps.

What version of BIOS is installed?

16 GB of RAM (4x4 GB) should be adequate for Win 10 and that's the max Dell validated on this model, though other users may have been able to get it to work with more.

Reboot and immediately press F12. Look for option to run diagnostics, including RAM and extended hard drive tests. Be patient, this can take a while... Copy error messages, if any, like hard drive smart test failed.

Assuming no errors, reboot Win 10 in Safe Mode and see if performance improves. If it does, something loading during a normal boot may be causing the problem.

How much free space is available on your hard drive? And when was last time you defragged it assuming it's not an SSD (never defrag an SSD)?

Dell doesn't support Win 10 on this model, so have you searched these forums to see if anyone has reported similar problems after upgrading the XPS 8300 from Win 7 to 10?

And see if those other threads mention anything about drivers because you're depending on Win 10 to install the right ones for this model, since there are no Dell drivers for Win 10 on the XPS 8300.

No, 16gb ram is fine. Go for the SSD upgrade.

My XPS-8300 runs fine with a 2.5inch SATA-III/600 SSD with Windows-10 (64bit) on it.

https://www.dell.com/community/Vostro-Desktops/Vostro-460-XPS-8300-Upgrade-Adventures/m-p/6055730/highlight/true#M1225

Put SSD on (fastest) SATA-0 port.

Personally, I would:
- Disconnect your C: drive for now (and keep as a backup).
- Drop a new SSD in there and clean-install Windows-10 and your Apps (fresh ... after all these years).

Compared to a spinning HDD  ... SSD speed as bootable C: will be like night-and-day .  And its not just booting ... Windows and Apps will load and run faster over-all.

I'll warn you that I just did this on a very similar 2011 XPS 8300.  I had no issues prior other then Windows had gotten dog slow (as it does) and decided 'why not'.  Bought a Samsung 860 EVO from Samsung.  Put a fresh copy of Windows 10 on it.  Drive looks perfectly healthy and suspect it is.  Windows constantly BSOD's with 'Critical Process Died' and will not create a dump.  I'm back using the old disk. So YMMV but it ain't always roses. 

The INTEL Driver for the current version of windows is no longer supported.  You cannot use the latest driver with a system this old.  Fairly sure 11.7.0.1013 is max for this model.  Clean install with intel chipset and intel RST driver in AHCI should be dramatically better.  Drive will not work correctly with the driver built into windows 10 1903.

• 17.5.2.1024
• 15.9.8.1050
• 16.8.3.1003
• 14.8.16.1063
• 13.6.0.1002
• 12.9.0.1001
• 11.7.0.1013

Beyond that changing the hard drive to SSD will improve things quite a bit.

https://www.dell.com/en-us/work/shop/accessories/apd/aa233476

https://www.amazon.com/Samsung-Inch-Internal-MZ-76E1T0B-AM/dp/B078DPCY3T/

You will want to mount it in a bay that replaces the 3.5 drive

https://www.amazon.com/SilverStone-SDP09-2-5-Inch-3-5-Inch-Hot-Swappable/dp/B0049MPQDG/

I was running 9.x.something, the same driver as with the non-SSD drive (also running Win 10).  I upgraded to 11.7.0.1013 and I'll see if it makes a difference. with BSOD.

Edit:  Exact same crash with 11.7.0.1013 so my warning stands.

I found a XPS 8300 in a e-waste (garbage) bin yesterday, and perhaps the previous owner threw it away because of the same reason. Too slow.

Fact is that the machine was just dirty. Believe me DIRTY. The GPU heatsink was 100% blocked and the CPU heatsink was very dirty as well.

SOLUTION:

I've disassembled the whole machine and gave it a good clean up. Dismounted the GPU, replaced the Thermal Paste and cleaned up the fan and heatsink. Same with the CPU. 

It performs like new, no noise, fantastic performance running Windows 10, and I tell you it is much faster than some newer machines.

Thermal paste have a lifespan of 5 years, after 5 years it starts to deteriorate, and the higher temperature your computer runs, slower it runs.

I'm in Melbourne, Australia and could do it for you for a small fee, but believe me, anyone with the right set of screwdrivers, thermal paste and patience can get it done.

I have an XPS 8300 and I can confirm what TTKDroid wrote, i.e., "It performs like new, no noise, fantastic performance running Windows 10". You may need to upgrade a couple drivers, see my post re XPS-8300 upgrade to Windows 10.