Nvidia plan to give the GTX 560 Ti, GTX 560, GTX 555 and GTX 550Ti all the End Of Life status once the GTX 600 series replacements have been launched.
The three sub GTX-660 GK106 graphics cards to replace them are expected in the August-September time frame. They will probably come in the form of the GTX 650, GTX 660SE and GTX 650Ti.
Whilst the market waits for these new 28nm replacements Nvidia hopes the remaining 500 series based stock is digested by the market in the meantime. There is still currently a lot of stock, hence why Nvidia introduced the GTX 560SE in order to offer a lower price point of card to shift stock faster.
Once that process of market digestion is mainly complete Nvidia is expected to issue an End of Life status on the above cards.
“A product discontinuation notification (PDN) is a formal notice to existing and prospective distributors that the company intends to discontinue a product, specifying a last date of accepting orders for it. After the very last of the orders are fullfilled (shipped), the product attains “end of life” (EOL) state.”