required to create an AGP-compatible graphics card. The inclusion of a bridge, and the need for a separate AGP card design, incurred additional board costs. The GeForce 6600 and ATI Radeon X800 XL, released during 2004–2005, were the first bridged cards. In 2009 AGP cards from Nvidia had a ceiling of the GeForce 7 Series. In 2011 DirectX 10-capable AGP cards from AMD vendors (Club 3D, HIS, Sapphire, Jaton, Visiontek, Diamond, etc.) included the Radeon HD 2400, 3450, 3650, 3850, 4350, 4650, and 4670. The HD 5000 AGP series mentioned in the AMD Catalyst software was never available. There were many problems with the AMD Catalyst 11.2 - 11.6 AGP hotfix drivers under Windows 7 with the HD 4000 series AGP video cards; use of 10.12 or 11.1 AGP hotfix drivers is the recommended workaround. Several of the vendors listed above make available past versions of the AGP drivers. By 2010, no new motherboard chipsets supported AGP and few new motherboards had AGP slots, however some continued to be produced with older AGP-supporting chipsets. In 2016, Windows 10 version 1607 dropped support for AGP. Possible future removal of support for AGP from open source Linux kernel drivers was considered in 2020. Versions Intel released "AGP specification 1.0" in 1997. It specified 3.3 V signals and 1× and 2× speeds. Specification 2.0 documented 1.5 V signaling, which could be used at 1×, 2× and the additional 4× speed and 3.0 added 0.8 V signaling, which could be operated at 4× and 8× speeds. (1× and 2× speeds are physically possible, but were not specified.) Available versions are listed in the adjacent table. AGP version 3.5 is only publicly mentioned by Microsoft under Universal Accelerated Graphics Port (UAGP), which specifies mandatory supports of extra registers once marked optional under AGP 3.0. Upgraded registers include PCISTS, CAPPTR, NCAPID, AGPSTAT, AGPCMD, NISTAT, NICMD. New required registers include APBASELO, APBASEHI, AGPCTRL, APSIZE, NEPG, GARTLO, GARTHI. There are various physical interfaces (connectors); see the Compatibility section. Official extensions AGP Pro An official extension for cards that required more electrical power, with a longer slot with additional pins for that purpose. AGP Pro cards were usually workstation-class cards used to accelerate professional computer-aided design applications employed in the fields of architecture, machining, engineering, simulations, and similar fields. 64-bit AGP A 64-bit channel was once proposed as an optional standard for AGP 3.0 in draft documents, but it