Abstract: In this paper we present a low-cost memory architecture running at 100 MHz which is suited for any PCI-based volume rendering accelerator using the ray-casting approach. Current SDRAM technology, parallel access to all voxels required for trilinear interpolation, a cubic addressing scheme, and a buffering mechanism accommodating memory latency are applied to achieve high frame-rates. A total of four off-the-shelf standard DIMM modules are required enabling up to 9 Hz (averaged over a representative set of views) for datasets of 256³ voxels, using early ray termination as the only algorithmic optimization. The presented memory architecture is a good balance of cost versus feasibility on a standard PC1 card - accepting data replication - and will be used for the VIZARD II ray casting accelerator.