You can not judge the amount of free ram in Windows 7 as a measure of how much ram you can use. W7 will use available unused ram as a cache and will gladly free it up if someone requests it. This confuses many people saying that W7 is a resource hogger, but this is wrong. It just uses HW you are not using to speed up tasks that will be coming (e.g. starting applications). This can be turned off (somehow) but I would not recommend.
Additionally I would NEVER go back to Vista as it clearly is inferior to W7 in many ways. Try to measure performance and not monitor artifical counters like used mem and you will see W7 should beat Vista in almost any situation.
Additionally I would NEVER go back to Vista as it clearly is inferior to W7 in many ways. Try to measure performance and not monitor artifical counters like used mem and you will see W7 should beat Vista in almost any situation.