Tom's had a full article on 6200 Turbocache cards, compared to the standard 6200 cards. Turbocache inhibitted performance by a wide margin, depending on the game, as much as 50% lower framerates I believe. But you'll want to look up that article.
Anandtech had a more recent comparison of both the 6200 Turbocache and a similar solution from ATI, both provided framerates below acceptable levels on modern games at 800x600 resolution, I believe 20 frames per second was about the average, with other performance-robbing graphics details turned off.
The cheapest card I can recommend for ANY games is the GeForce4 Ti4200. That's 3 years old! You might be able to find one for $50. For around $65 (if you look hard enough) you can find an ATI Radeon 9550 with 128-bit memory interface (64-bit versions are inferior performers as well).
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