Having used a memory optimizer ( Win Cleaner) I can only get an absolute max recover to 65% ( averages 60% ) free memory with 4gb Ram.when at the same virtual memory useage is zero . I can see prefetch being part of the problem and have changed the prefetch priority between apps / boot /or both. Previously with 32 bit Vista and 2GB of Ram I could recover 80 to 96 % Tweak V1 shows 96.1% free (ie 1923Mb) today on attempted memory recovery, suggesting that only 2GB is available. Sandra and Win Cleaner Memory Optimizer both show 4gb being used . Seems like a possible false reading. Any advice would be appreciated.