If I have hundreds of job postings will there be a significant slowdown in the loading time on my website?

Our themes are well coded using WordPress best practices and standards and therefore score very high on Google PageSpeed.

If you are using a low quality shared hosting environment ($3 - $8 per month) and have a large amount of job postings then you may notice your website is taking some time to load. You can reduce the slowness by using a caching plugin that will reduce the load on your server. 

If you are using a good quality host that offers server side caching and is built for performance then you will not have any issues with slowness.