The real question is:
What do you need it for?
I wouldn't really care about the processor, as long as you don't do anything requiring an intensive processing power.
You can find a lot of cpu comparing sites by searching on any search engine "cpu compare" or "cpu benchmark".
The SSD will gargantuanly benefit the performance. The computer will start faster, the programs will start faster, everything will be faster. But with 250GB you may not have enough space, depending on what you do. Do you store photos, videos and bigger files on your computer or do you use cloud services? If you don't, with time you may run out of space without an external hard disk. Meanwhile, the 1TB hard disk will give you a lot of space.
Also, could you post the specific model of processors in your post? I don't yet have enough reputation to comment.
I've used this website and Intel's official catalogue of products for a comparison, take a look as they are very helpful.
The main difference between the 2 is the number of cores. The 7th generation one got 2 cores while the 8th generation one got 4 (I'm talking about physical cores, not thread or "virtual" cores). Remember that they are both low-end cores, so you may have problems calculating, as you said in the comments, macros or data in number of millions, with both of the computers. Still on a Windows environment an SSD will be a greater advantage compared to a slower-quad core processor, as Windows is very resource demanding when talking about hard disks speeds (I'm looking at you Cortana).