the only way to improve performance in a cpu-bound title without upgrading the cpu would be to overclock, but that's not possible with an i5 650

you're gonna have to make an upgrade more than likely

What do you suggest I upgrade to?

that i would page setsul for, you can make a post in the pc build thread with your budget and he'll help you out way more than i can

I have been summoned.

I'm not sure what you expect. You've got a CPU, said CPU doesn't cut it for TF2 anymore but you don't want to lower settings either. It just doesn't work. You can try sprinkling fairy dust on the CPU but I doubt you have some on hand.

Without getting a new CPU your only options is overclocking but I'm not sure if your motherboard supports it.
Otherwise new CPU is your only option.

Why are you surprised though? You knew how much fps you were getting before buying a 144Hz monitor. Did you expect them to magically increase?

I am definitely NOT surprised with the outcomes. I decided to get a 144hz monitor, because I knew it would increase my hit/miss ratio with below the required fps or not. Now, since I got everything I need, I am looking to get a new CPU. The budget I have for a new CPU is 250-300 USD. I am looking for a CPU that can cap TF2 up to a desirable FPS for 144hz, (289 fps) that can work in unison with my graphics card.

The tearing is most likely making it look worse than before now actually, so I really think you bought in the wrong order, but I guess that's none of my business.

You'll need a new motherboard as well. So what size does your case support?

EDIT: Zen hype is destroying my sentences.

My PC was bought years ago not custom built. Just recently the parts were added, so the motherboard, and case are the same as they had came originally. My friend on Steam suggested me to get a new motherboard AND tower. I'm not totally sure what size my case supports, but I can tell you the motherboard it came with. It's the Dell 033FF6. I want to do what I can with the case, though, because I really don't feel like rebuying everything.

My computer is pretty crappy as it's pretty old, but I'm willing to build it up more. As for the model itself, it's an Inspiron 580. Hope that helps.

That should be a µATX mobo so I'll go with µATX to be safe.

The reasonable choice would be this:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i3-6100 3.7GHz Dual-Core Processor ($110.99 @ SuperBiiz)
Motherboard: ASRock B150M Pro4S Micro ATX LGA1151 Motherboard ($73.99 @ Newegg)
Memory: G.Skill NT Series 8GB (2 x 4GB) DDR4-2400 Memory ($34.98 @ Newegg)
Total: $219.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-08-19 17:43 EDT-0400

You'll probably have to use an fps config anyway to get stable fps. That's just TF2.

Now you could get a different mobo that would let you keep your RAM but because TF2 is weird the RAM should actually get you more of an increase in fps than a 40$ more expensive CPU.

That's not saying there aren't any faster CPUs. But we're talking 5% for 50$ in case of an i3-6320 and 60$ on top of that for another 5% with the i5-6600. Twice the money for 10% just isn't worth it imho (only +50% if we count mobo and RAM, still not worth it).
Fun fact: The i5-6500 should actually be slower than the i3-6320 if TF2's behaviour hasn't changed since the last time I tested it.

Alright, I will look more into this. You sure that these parts would fit with the size of the case? I don't want to buy the parts, open it up and find out they're too big.

If the Internet was right then your current motherboard is µATX. The one I recommended is also µATX. Same size. That's what standards are for.