I wasn't really referring to load speed above, just using SVG & image code within the inner HTML of a Hype object. To answer your question: it depends. If you embed your SVG code within the inner HTML of an object it will download during the initial download of the generated JS file required for loading your hype document. If your SVG file is huge, this will slow down this initial load. If it is small, you won't notice the difference and you should embed it if you want as much speed as possible. Adding an SVG file to your resource library requires an additional HTTP connection to download so if you have many many SVGs downloading from the resource library this will be slower then embedding those (small) SVGs inline. We're talking maybe 100 millisecond difference on most connections.
Why are you using base64 for embedding images? Are you not allowed to load any images in your setup? This will drastically increase the amount of data needed for loading your images.