If your model is larger than this you will need to build a lower detail version for the viewer. Believe it or not, there are benefits to this. Remember, this model is a viewing model for the web. In the model description let the potential buyers know that the actual model may have much higher detailed textures and geometry. Texture is another way that you can make your model perform better in the viewer.
Texture consumes large amounts of memory and as such, affects performance.
You may have a high performance graphics card and cable modem, but unfortunately, most of those who visit the site will not. It is therefore advisable to reduce the amount of texture memory used in your model. You can reduce texture by reducing the size of the textures or by combining them. Combining them is great but requires re-texturing your model. Reducing the size of the textures is therefore the best route to take.