Site performing slowly the more products i add

I run a clothing store and i have hundreds of products, each product has usually a couple of colours and few sizes. The list of variants when i add the characteristics 'Colour' and 'Size' now is close to 1000 variants each product. I then go and delete alot of these to get it down to the few variations relevant to the product.

I have found that i think because of the characteristics/variants it may be quite resource intensive on my website and have noticed quite a considerable performance reduction in my site as i have been adding more products to the site.

It would be good if some sort of optimisation of the product/variants code could be achieved to help the site run better/faster in the future.

cheers