Speed issues, UNO with 3.5" TFT vs Mega with 3.5" TFT

I started my journey with Arduino using an UNO and a 16x2 LCD while learning the basics. At the same time, I ordered a Mega2560R3 and a Kuman 3.5" TFT with touchscreen.

With the TFT plugged into the UNO and running the graphictest_kbv.ino from MCUFRIEND, the whole thing from start to finish takes approximately 2 minutes and 14 seconds. At one point early on, the screen displays what looks like an info screen telling me how many operations it carried out and how long it took. It says it took 1 minute and 14 seconds when in reality, it only took 41 seconds.

I then used the same code, compiled for the Mega and plugged the TFT into my Mega and ran exactly the same test expecting it to run at least as well. I couldn't have been more wrong.
This time around from start to finish was 3m 32s and the info screen displayed 1m 36s but actually took 1m 14s. The software scrolling was especially slow and jagged.

I Then tried the colligate_test.ino from LCDWIKI_KBV as this was what was in the instructions for the screen and again had similar results. On the UNO, the test ran quicker and smoother.

Is this to be expected or is the code UNO specific? Admittedly, both of my units are not genuine Arduino but even so, I would have thought the Mega chipset should have performed as well as the UNO?

What pins are you using? Maybe you can use SPI pins on the UNO but not on the Mega.

I have experienced the same difference between Mega & Uno on the TFT screens using the MCUfriend library. No idea about the cause.

I always thought the Mega was a bit of a dinosaur.

-jim lee