ATI Partners will start launching overclocked versions of Radeon HD 5870 cards starting today, but more cards will get announced later this week.

The reference speed was 850MHz and that people told us that you get some decent overclocking performance out of the chip and can reach close to 1GHz, but it will most likely ship under the magic 1000MHz barrier.

We expect some modest overclocking this week, but there will be some space for faster versions in the weeks to come, still in 2009.

Unfortunately, these cards will also face tight supply, as ATI still faces some huge shortages of its 5xx0 generation 40nm DirectX 11 cards, and there are no any indications that things will get better in the short term.