WP and WP MU slow speed

Hi all,

We are trying to build a software product library using WP, the estimated number of records should be around 300,000 records if not more

When we tried a pilot project by adding like 2000 records as ‘posts’ with custom fields and while using plugins like WP Cache or WP Super cache, the loading speed of the testing site home page was dramatically slow to the extend that it can go up to 20-30 seconds

Searching and finding products inside was something like a dream due to site speed

I must say that each product have at least 15 custom field with it, none of them are images (meaning we don’t load images to DB, but we put paths to images on other websites whom allow us to do so)

So can someone please recommend a solution to overcome this problem?

Thanks in advance for your time