Perhaps a RAM test board. It has 'Siemens' RAM which is not common on 3dfx cards. Notice the Avenger chip (or actually not), it's removed. It also lacks a FET.
The board has an engineering sample attached which says 'locks instantly in Quake 3'. The RAM test probably failed somehow on which someone decided to remove the Avenger chip 
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In case you want to run Windows 9x or 2000 on a slower system you'd better install the 3dfx Voodoo4/5 V1.04 reference driver first. In case you run Windows XP and/or a faster system (AMD Athlon 1400MHz or faster) the latest SFFT driver might be a good idea.
Those who want to run the Voodoo3 3500TV better download their driver here. The Voodoo3 3500TV uses TV functions which require special drivers. As the Voodoo3 3500TV is unique in one way, less driver support can be found. Most people don't use the TV functions anymore these days.
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