Currently have late-2011 macbook pro. What is comparable to it?

That does not sound like you are out of compute power -- it sounds like you are out of RAM.

How to use Activity Monitor on your Mac - Apple Support

use Activity Monitor when you have all that stuff loaded up. I expect you will be more than 75 percent idle on CPU, and three times overcommitted (swap used) on RAM memory.

And if true, you could upgrade your current Mac to 16GB for under US$160, and get a few more years out of it.

...and for another about US$150, upgrade to a low latency SSD and have all of those Apps humming right along (may be not flying, but not lagging).

I currently have a late 2011 Macbook Pro

I don't want to look at something that's less of a computer because I'm pushing the limits on this one now. Thanks for the help.

Start here: https://www.apple.com/mac/

Hello,

There are some improvements in architecture, and new features like Touch ID and the TouchBar. Depending on how much you want to spend, you can get 6 cores now. Newer machines can support more RAM and have SSDs. Your machine has upgradeable RAM and you can install an SSD. But Apple’s new, built-in SSDs are faster than any SSD upgrade for an older machine.

What about the difference between the processors? Is the i7 I have really that much different from the current i7's?

Your machine is 8 years old. The difference in technology over 8 year in the computer world is literally light years apart— so to answer your question—yes.

What about the difference between the processors? Is the i7 I have really that much different from the current i7's?

The differences in processors is not that significant. All those processors have much more power than you could use. It is all the other architecture updates that make the difference. The processor itself (on old or new machines) is limited more thermally than anything else. You will be throttled due to overheating long before you reach the limits of the CPU.

You mentioned "slow down or even stops running all together”. That sounds like both RAM and hard drive limits. You are running out of RAM. When that happens, your computer uses your hard drive for virtual memory. That is when you hit that dead stop. An SSD would really help with that.

Do you want to spend a few hundred dollars for a machine that is 4 times faster, but could fail for other reasons due to age? Or spend a few thousand for a machine that is 8 times faster and has a warranty?

<<"because I'm pushing the limits on this one now.">>

Could you please explain in what way you are "pushing the limits of this one" ??

Exactly how is it falling short of your expectations?