The fact that Ati decided to postpone the arrival of the R600 had a curios effect on its main integrators. Because there was no way to fight Nvidia's G80 series, they decided to extend the RV520/580+ line by adding several flavors of the same products, some of them used non-reference cooling while others integrated passive heatpipe elements.
HIS' X1950 XT was built using the reference board but instead of developing a stock cooler, they replaced it with the 3rd version of ICEQ cooling system. Dubbed ICEQ3, this is actually a hybrid cooler using both heatpipes and fans in order to ensure the best overclocking experience. Speaking of which, this X1950 XT in its ICEQ 3 version is able to sustain some impressive clock speeds. Overclockers will simply love this card because they can improve its performance without having to use additional cooling.
The GDDR3 chips use the standard memory interface (256-bit) but unlike older X1950 versions, the XT comes with some impressive clock speeds (1800MHz- DDR). The GPU has the same clock speed as the XTX version (650MHz) but with the help of the ICEQ cooling unit it is possible to push it over the 700MHz mark (which is pretty much the limit for a 90nm GPU).
Because the GDDR3chips use the classic memory ring interface (256-bit) the resulting memory bandwidth is 57.6GB/s. Overall the RV580+ chipset produces some impressive numbers especially when rendering HDR scenes with AA and AF options on. Moreover the Avivo engine helps a lot when you're watching a HD movie as the card is able to offload some threads from the CPU (this helps only when watching VC-1, H.246 and WMV-HD sources).
Currently you can buy the ICEQ 3 version of HIS' X1950XT video card for about $285-$299. If you take into account that this product also offers a lot of headroom for overclockers the price range is really good. Unfortunately these cards are pretty rare so you have to be really lucky in order to get one for yourself.