One explanation I like is comparing cpu with superman and gpu with 1000 normal people. The cpu is powerful and can perform lots of instructions just like superman can lift heavy things easily. Gpu can perform simple calculations parallely just like 1000 children who are taught to do math calculation can outperform even superman or cpu if you can divide a task. The pixels need individual calculation. Cpu is slow because it is a single one or its cores are countable in hands which is doing the task. Gpu on the other hand has a lot of small micro cpu with a lot of core count. 1050 ti has about 768 cuda cores.