Firstly could some one help me with what specifically this 'wait time' is. e.g. php render? browser render ? can i do anything about it?

Should i be looking to implement page cache to reduce this 'wait time'?

While my site feels pretty fast, I have been getting more and more concerned about the figures shown on tools.pingdom.com,

I appreciate it would be somewhat difficult to help given i'v chosen not to include my magento domain, but I feel the question is generic enough to apply to all who run magento. I did consider posting in the general webmasters thread, but since this is a dedicated magento store, i felt it best to start here.

Image attached.

Firstly could some one help me with what specifically this 'wait time' is. e.g. php render? browser render ? can i do anything about it?

Should i be looking to implement page cache to reduce this 'wait time'?

While my site feels pretty fast, I have been getting more and more concerned about the figures shown on tools.pingdom.com,

I appreciate it would be somewhat difficult to help given i'v chosen not to include my magento domain, but I feel the question is generic enough to apply to all who run magento. I did consider posting in the general webmasters thread, but since this is a dedicated magento store, i felt it best to start here.

External Tests

http://tools.pingdom.com

http://gtmetrix.com/

https://developers.google.com/speed/pagespeed/insights/