Need some suggestion to reduce server response time

i installed wordpress, my domain and hosting are bought from different providers. site takes 2 to 10 second to respond, though i optimized my blog for quick loading due to high server response time i m getting google pagespeed score only 50 to 60. i need some suggestions to speed up response time, if i set DNS A record instead of Nameserver will it give any difference?

You should use a CDN (Content Delivery Network) service like Cloudflare: https://www.cloudflare.com/

If its wordpress how many plugins do you have installed, is it image heavy (and what size are the images). Like 1337WuLF says, a CDN may help if it is indeed image heavy.

Are you running this on shared hosting, VPS or dedi - if its shared then the server may have a lot of accounts on it and abusing resources.

Lots of variables in this so its not quite that simple to track down

i just transferred the wordpress to new hosting and issue is resolved now ...

Well I'm not sure how you are doing it but I use the google PageSpeed Mod compiled into Nginx on my servers. Might be helpful to you.