MartinC wrote:This my concern:
Swapped hardwired DirectX 7 T&L Units + DirectX 8 integer pixel shader units for DirectX 9 floating point units.
This is the difference between the old 5600 & 5900 cores. Now having swapped the DX integer for DX float make me wonder if conversions would need to be done for DX 7/8 games with possible degraded quality, this a concern considering <DX8 games are the target.
The FX series was a mismash of older and newer functions. Apparently it had DX7, DX8 and DX9 hardware. What ATI did instead was build a pure DX9 card and translate the older functions into DX9 vertex/pixel shader code. History showed that this was the way to go. There is no tangible loss of speed or quality for older games, and the ATI R300 GPU was way better for new games.
5700/5900 tried to shore things up by swapping some of the retro hardware for more DX9 ALUs. It helped just enough to put 5950 Ultra basically at parity with the Radeon 9800XT. Assuming you could ignore all of NVIDIA's visual quality cheats that the entire FX line shared. The FX 5900 series also had way more memory bandwidth with the then brand new GDDR3, all in an effort to match up.
The FX series is decent for older games. The higher FX cards are very fast and quite compatible with many games. Issues that arise will be caused by driver quirks. Games usually need special attention from driver writers and as a game gets older it doesn't get that attention anymore. Any newer card from any vendor can be troublesome in that way.
A Voodoo5 5500 is probably the best option for old 3D gaming as you get Glide as well as good anti-aliasing, and you are spared from AGP issues for the most part because 3Dfx didn't mess much with AGP features. Super 7 motherboards almost universally have terrible AGP implementations. Even a quality 440BX mobo can be trouble with some cards.