Reduce the image size. You surely don't want your customers to download dozens of 18 megapixel images just to see spinning products. That won't be the kind of user experience that makes people reach for their wallets. And if you don't need all that resolution, you don't need to record it all in the first place. Try smaller images.

Use an intervalometer to reduce the rate at which the camera takes photos. You don't need 204 frames (3.4frames/sec * 60sec) to produce a useful animation. Figure out the angular distance you need between frames to get the effect you want -- many sites use 15 or 20° between frames, but even if you go down to 5° you'll cut the number of frames from 204 to 72. Then calculate the interval you need between shots (60 sec/72 frames = 0.833 sec), and set the intervalometer to that rate. Slowing the rate down this way will give your camera time to write the images out to the memory card.

Get a faster memory card. If you're using a card that's slower than your camera's max write speed, using a faster card is an easy way to speed up the write process.