How can I improve framerate of Minecraft client?

You can change your draw distance in the options.

Within the options menu (Esc -> Options), set Graphics to Fast and set Render Distance to Tiny.

Close any programs you can spare to lose (ie internet browser, messenger, music).

If you're really desperate, you can open your task manager (Ctrl + Alt + Delete -> Start Task Manager) and select the "Processes" tab. Order by "Memory" and have a look at what's taking up so much processing power on your computer (Minecraft will be listed as javaw.exe). Use the End Process button to stop a selected process.

Do not end any processes that you don't know what they are. Have a look at the "Description" tab, and if you know what the process does, and you know you don't need it, then end it.

Of course you can change your render distance and the graphics quality, but for many, like it seems for you, the speed still is not high enough.

Now, I'm assuming that you do not have a great graphics card. For some graphics cards, like Intel HD, you will not have a chance of speeding it up without modifying the game. Optimine is common in that case. Link

If by chance you have an Intel Graphics Media Accelerator, there is another opportunity for you. GMABooster is a nice program which can boost your graphics speed quite a bit. Link

If graphics isn't your problem, and you have a slow processor/low RAM, you could try the following:

• Do not multitask. Only have Minecraft open, and don't run it in your browser. Close all programs that you don't need, even those that are behind the scenes.
• If you don't mind the lack of monsters at some times, turning the game on peaceful will reduce some load on your CPU, but of course, it takes away monsters, and that's boring!
• Change Minecraft's processing priority. A good tutorial to do that is here: Link

So that's all I can suggest. If all else fails, you might have to upgrade your computer. You can get plenty of cheap, new choices at Amazon.com.

(Plus, you could try all of those at once! The processing priority change works the best for me. I have Intel HD, and I can run Minecraft pretty smoothly.)

McRegion v5 mod optimizes how chunks are stored on the disk, meaning pauses to load or save a chunk as you move around a world become much shorter and less noticeable.

Your beta copy of minecraft already includes the FastRender mod; which has been improved to Optimine.

As with all mods, they break when minecraft version increments.

On windows 7, I set minecraft to run in Compatibility Mode as Windows 2000. The improvement was remarkable!

Use FasterCraft; go here and download the version appropriate for your version of Minecraft.

Even though this question has already been answered I think people here left out defragging the folder of MineCraft(don't use on SDD drives), and I think McRegion does that too but programs like Defraggler can do it better. Defragging the folder will put the files closer to each other, so loading things will be a lot faster.

Go to your .minecraft folder and search for the options file. Open it and search for:

fpsLimit:0

It will be set at 0 (most likely) so change that 0 to 60 and the fps shouldn't (based on your computer) go below 60 fps

To reduce lag on the client side, you should set render distance to Normal (or shorter if you have an older computer), set graphics to fast, disable clouds, turn off smooth lighting, set performance to balanced, turn off particles, and, if you have a newer computer, turn ON Advanced OpenGL. If you still have lag, you can grab OptiFine (use the light version if you just want an FPS increase, otherwise go ultra) and add it to your game, which should massively increase your FPS.

Since the first 1.13 snapshot you can set your fullscreen resolution. And of course you can resize your window to be very small. Both help enourmously, the smaller the window (or the lower the fullscreen resolution), the faster is the game.