Is this processor for real 3.1 GHz only $64?

Well it is from Newegg and not one of those other companies that sell through Newegg.

It might work in your computer, though the Dell specs only listed the previous generation Core 2 Duo up through the 7000 series and not the 8000 series. Same socket, FSB, and power requirements though.
 


What's your point?
 
Legitimate, but not a great deal.
E8500 is available on ebay for $12.88, not $65.
Dell shows the strongest supported cpu to be the E7200 which you can buy on ebay for $3.
What cpu do you now have?
CPU-Z will tell you.

It is time to replace your pc. A modern skylake G4400 is approximately twice as strong and costs the same $65.
Yes, you will need other parts to go with it.
 


The point is, if it works great, if it doesn't that your money. But still a waste of money for upgrade for gaming.
 


Are there any good CPU's with an LGA 775 socket? Also it is 3.1 GHz so how is it bad and why would it be so cheap...
 

Unless you're comparing processors with the same microarchitecture (e.g. two 6th gen Skylake i5s), you can't look at clockspeed to compare performance. Performance depends on both frequency as well as a metric known as instructions per clock (IPC) (and a few other things). Modern CPUs have significantly better IPC, so they perform much better at a given clockspeed. A modern dual-core CPU clocked at 3.1 GHz would be far faster than that CPU, and even modern dual-cores aren't recommended for gaming these days.