prestashopvss

It is really deadly slow compare to 1.4.6 version. I install the 1.5.2 at a dedicated server using memcache 640M; And it's even 2 seconds slower than the magento on the same server!! And 1.4.6 is normal faster than magento before upgrade to 1.5.2!!! Is there an solution? Otherwise, I have to consider using opencart, which is very light-weighted and faster for small shop with limited sku