64GB RAM won’t speed up Cycles renders unless your scene is enormous.

No, not unless your current scene doesn’t fit in 32GB.

Blender Cycles uses RAM to store geometry, textures, and the acceleration structures needed for rendering. If your scene fits comfortably in 32GB, adding more won’t make the CPU or GPU go faster. Rendering is compute-bound, not memory-bound, once you have enough RAM to avoid swapping.

Where 64GB matters: if your scene is big enough to push past 32GB, the OS starts paging to disk, and that absolutely kills render times. In that case, 64GB is the difference between completing a render and watching it crawl. But for most Blender users — even heavy ones — 32GB is plenty for CPU+GPU rendering with Cycles. The bottleneck is usually the GPU itself.

If you’re routinely working with multi-million polygon scenes, 8K textures, and hundreds of instances, sure, go 64GB. Otherwise, spend that money on a faster GPU. That will actually cut render times.

Unless you know your scene needs it, 64GB is overkill.