R100, but improved with trilinear filtering and some other refinements. However, it is still highly angle-dependent and the driver sometimes forces bilinear filtering for speed. NVIDIA's GeForce4 Ti series offered a more accurate anisotropic implementation, but with a greater performance impact. R200 has ATI's first implementation of a hardware-accelerated tessellation engine (a.k.a. higher order surfaces), called Truform, which can automatically increase the geometric complexity of 3D models. The technology requires developer support and is not practical for all scenarios. It can undesirably round-out models. As a result of very limited adoption, ATI dropped TruForm support from its future hardware. Performance Radeon 8500's biggest initial disappointment was its early driver releases. At launch, the card's performance was below expectations and it had numerous software flaws that caused problems with games. The chip's anti-aliasing support was only functional in Direct3D and was very slow. To dampen excitement for 8500, competitor nVidia released their Detonator4 driver package on the same day as most web sites previewed the Radeon 8500. nVidia's drivers were of better quality, and they also further boosted the GeForce3's performance. Several hardware review sites noted anomalies in actual game tests with the Radeon 8500. For example, ATI was detecting the executable "Quake3.exe" and forcing the texture filtering quality to a much lower level than normally produced by the card, presumably in order to improve performance. HardOCP was the first hardware review web site to bring the issue to the community, and proved its existence by renaming all instances of "Quake" in the executable to "Quack." However, even with the Detonator4 drivers, the Radeon 8500 was able to outperform the GeForce3 (which the 8500 was intended to compete against) and in some circumstances its faster revision, the Ti500, the higher clocked derivative Nvidia had rolled out in response to the R200 project. Later, driver updates helped to further close the performance gap between the 8500 and the Ti500, while the 8500 was also significantly less expensive and offered additional multimedia features such as dual-monitor support. Though the GeForce3 Ti200 did become the first DirectX 8.0 card to offer 128 MB of video memory, instead of the common 64 MB norm for high-end cards of the time, it turned out that the GeForce3's limitations prevented it from taking full advantage of it, while the Radeon 8500 was able to more successfully exploit that potential. In the end of 2001, to compete with