Pay attention to the issues Nalates Urriah brought up. She is spot on in her advice. Lower your Bandwidth to 1500. Lower your LOD factor to 2. There are two other things i wanted to mention based on what I see in your settings. You can increase Texture memory from the 512MB default to match the amount of memory your graphics card comes with. You can increase your computers system memory from the 8GB you currently have to 16GB. In an empty region 8GB is fine but once you go anywhere that is busy with many avatars the memory used quickly zooms way past 8GB. Memory is cheap these days and this upgrade to 16GB will make your SL experience smoother and more responsive across the board. The last thing is please do a speed test and post your upload speed and download speed and ping time. Ping time has already been brought up and posting that is important and will give much insight.
I noticed a small bug problem with Marketplace WISHLIST. I cannot add 0L items to the Wishlist from the marketplace item listing page. The 'Add to Wishlist' button is missing for 0L items. Thankfully, the Favorites page has a 'add to Wishlist' button that works and will copy 0L items from Favorites to Wishlist. If this is being done purposefully, I would sure like to understand the thinking that feels that 0L items should not be in the Wishlist. What is wrong with wanting to save a 0L item in the Wishlist so I can decide another time if I want to buy it or not.