Dell or Crucial are the best places to buy ram for Dell computers. They sell the exact ram for your older model. Not all ram will work. Dell might not have ram for older models but Crucial has it.

Any ole ram wont do.

Must not be High density and must be newer spec

SNP66GKYC RAM

https://www.amazon.com/Dell-Certified-Replacement-SNP66GKYC-8G/dp/B009MMPCN2/

https://www.amazon.com/Arch-Memory-Certified-SNP66GKYC-A6994446/dp/B07482PLVQ/

Works with

• Alienware X51
• Alienware X51 R2
• Inspiron 3647
• Inspiron 3847
• Inspiron 670s
• OptiPlex 3020
• OptiPlex 3030
• OptiPlex 7010
• OptiPlex 9010
• OptiPlex 9020 DT
• OptiPlex XE2 MT
• OptiPlex XE2 SFF
• Vostro 470
• XPS 8500
• XPS 8700

The same memory works perfectly fine in my Dell XPS 8700.

I have a much older Dell Inspiron 3847 and I would like to know if adding memory is better than going out an purchasing another desktop.  I am not computer savy, yet I have added memory in the past on previous computers.  Dell, of course tells me to buy new because mine is older, but if I can save some money right now and adding memory could help, I am all for it.  I have gone to the link you suggested on Amazon, but not sure which I need to choose.  I appreciate any and all help you can provide and I would be so grateful for the truth as well.  Thank you!!!

@brandnewme,

What CPU do you have in that machine?  That model it takes the full range of Intel's CPUs from the weak Celeron to the quad core i7.  Now, it is the 4th Generation Intel CPUs so Windows 11 is out of the question (at least not without some tricks that bypass that imitation - at least for now).  But, it really depends on how YOU feel about your machine.

Also depends on how much ram you have now, and how the existing slots are filled (both used or just one).  If you have just 4GB, doubling it to 8 will give you some benefits.  16Gb might be better.  But that will be the sweet spot.  More than that is not much benefit anymore unless you are doing CAD, Building Information Modeling, or hard-core gaming.

Thanks for your reply.  I went online and was told this was compatible and adding it would help.  If not, I can return.  At that point I will probably just purchase a new desktop.  Just trying to save myself some money right now, and this Crucial RAM 8GB DDR3 1600 MHz CL11 Desktop Memory CT102464BD160B might help me!  I am not very computer savy, so just having some better memory could help.  

@speedstep​ I picked up the ram from the first link for the dell inspiron 3847 and my system wouldn't boot after installing them. Before that I changed the ssd, and added a gpu all at the same time. The power button flashes orange twice with the new ram in but runs when I swap back to the old ram. Is there something I need to do to get it to work?

@speedstep​ Helpful this is thanks!  My systems information shows that I have 12 gigs already.  My max is 16 gig so only 4 more gigs.  How would an 8 gig be sufficient?  Would it not accept it and not work with the additional 4 gigs that 8 would provide?