True.  I couldn't verify with userbenchmark, but eBay and Amazon both have 3010 refurbs with I7's.

The i7 2600 and i7 3770 works fine with the 3010 MT.

Can you confirm that? Optiplex 3010. How much ram is that running?

Core I5 3450 is listed as max for 3010.

Slots: 2 (2 banks of 1)

Maximum Memory: 8GB

https://www.crucial.com/usa/en/optiplex-3010-desktop/CT3456097

Specs: DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 512Meg x 64 •

https://www.dell.com/downloads/global/products/optix/en/optiplex_3010_technical_guidebook.pdf

Unbelievable how tone deaf this response and others like it are.  If someone can't look up factory specs on their own, they shouldn't be working on a computer.  The user is asking who has tried upgrades beyond the factory spec and what has worked.  Dell specs for this computer say max ram is just 8GB however, 16GB will work fine (2x8GB).  That is the only kind of information that is helpful here. I'm surprised you didn't just say "Throw that old thing away and go out and buy a new Dell." That's pretty much what you did.

https://www.crucial.com/memory/ddr3/ct2k51264bd160b/ct7341154

\https://www.amazon.com/Crucial-PC3L-12800-Unbuffered-Memory-CT2K51264BD160B/dp/B005NU49DG

Hi I have a 3010 and I want to know if I can put an i3-7100 in it. The manual I think isn’t updated for later models of the i3 for example ones made in 2017 (i3-7100). I’ll continue to research, but if anyone knows please let me know!

Optiplex 3010 Tech Guide 

The 3010 is limited to 3rd gen.  7th gen is way too new for it.

If you want to upgrade to 7th, you might consider newer PC.

If you research, you might some stretched it to the i7 3rd gen.

https://www.ebay.com/itm/Dell-OptiPlex-3010-PC-i7-3770-3-4GHz-8GB-RAM-2TB-HDD-Win-10-Pro-SD-Card/324441907676?hash=item4b8a3ea1dc:g:8lkAAOSw3yJf85nu 

https://www.newegg.com/p/pl?d=Optiplex+3010+i7 

Links have some Optiplex 3010's with i7's.

If you go with an i7-3770, be sure to have the latest BIOS for your 3010.

Do you need a better cooler after upgrading cpu or will the stock one do fine

Re: Do you need a better cooler after upgrading cpu or will the stock one do fine

stock cooler is supposed to cover up to 77w of i5. i7 has same TDP as i5.

i7-3770, 77w

dell 3010 spec:

Intel® CoreTM i5-3450 / 3.10GHz, 6M, VT-x, 77W
Intel® Dual CoreTM i3 Processors
Intel® CoreTM i3-2130 / 3.40GHz, 3M, VT-x, 65W
Intel® CoreTM i3-2120 / 3.30GHz, 3M, VT-x, 65W
Intel® CoreTM i3-2125 / 3.30GHz, 3M, VT-x, 65W

I'm late, my apologies.  Also new on the board, so there's that.

I'm running a 3010.  The I3-3220 was awfully slow, and I happened to have an I7-2600 in a machine that currently isn't running, so I swapped.  The I7-2600 runs fine, although it does run a little warmer than the I3 did.  I'm considering a different CPU cooler, but haven't pulled the trigger yet.

As for RAM -- this machine had 4 GB when I got it.  The first time I used it, I opened too many things at once and instantly saw what happens when you run out of memory.  I looked in that same old computer where I got my I7 and found an 8 GB stick.  I put it in alongside the 4 GB stick it came with and now I'm running 12 GB RAM.  It runs much better, but as you would expect, mismatched RAM doesn't really perform up to its potential.

I'm not even going to mention my HD5450...

Top listed CPU for the 3010 is 77w.  An I7-3770 is only 77w.  The I7-2600 is 95w.  Better cooling is not a bad idea.  Sounds like you're keeping an eye on the temp.  One option also is a fan or 2 can always be added to the tower, 1 if you're using GPU card.  Better heatsink will be even more effective.

It's not mentioned what machine you transferred parts from.  But as long as the RAM is working, if it's the same speed, then chances are it's at it's full potential.  You might know, RAM operates at the speed of the slowest stick.

Speed generally may not have much improvement beyond 8GB, unless more is needed for certain applications.  If not in use already, an SSD will give noticeable improvement is speed.