Texture quality
We've seen that 128MB cards can be advantageous in certain situations, especially when game content includes big, high-detail textures that will quickly fill up a 64MB card's memory, but what to these textures actually look like? Is there really that much of a difference?

Jedi Knight II's High (left) and Very High (right) quality textures

Yes, there is, and Jedi Knight II is a great example. The "Very High" detail textures on the right really do look much better than the "High" detail ones on the left, and the difference is noticeable during normal gameplay, as well. Click here for an uncompressed version of the above picture.

Conclusions
If clock speeds are equal, there's definitely a benefit to getting a graphics card with 128 versus 64MB of graphics memory. Of course, prices for cards with different memory sizes aren't going to be the same, so how much more you're willing to pay is going to come down to how much you want to future-proof your purchase. As we saw in our testing, newer games are making use of extra graphics memory when it's available. Future titles, whose geometry and highest-detail textures should easily saturate 64MB of memory, will only further widen the performance gap between 64 and 128MB cards.

Now, you're not hurting too bad if you already have a card with 64MB of graphics memory. You can still run current games quite well, and you do have the option of turning down texture quality settings in some applications. However, if you're shopping around for a card now and you want it to last, springing for a 128MB card is probably a good idea.

For a GeForce4 Ti 4200, the price premium for 128MB cards is only about $20, though you will have to overclock your memory from 222MHz to 250MHz to get the results we did today. For a Radeon 8500LE, the price difference is $20, as well. ATI's latest Radeon 9000 Pro also comes in 64 and 128MB flavors, but the price difference there is closer to $50, which might intimidate some. However, the Radeon 9000 Pro 128MB is pretty new on the market, and we could see the price drop significantly over time. We didn't test the Radeon 9000 Pro today, so I can't speak for its performance specifically, but it should be close to that of the Radeon 8500LE in terms of where extra memory makes a difference and where it doesn't.

It feels weird saying this, because it seems like only yesterday that 128MB graphics cards even became available, but serious gamers should really only be looking at 128MB cards. Sure, a 64MB will run current and future titles, but you might have to turn down the resolution and detail levels to the point where it looks like you're playing one of last year's games, just to keep your frame rate in check. Where's the fun in that?