Geneious has pretty high memory and CPU requirements. It is becoming increasingly impractical to run it on 32 bit hardware since the realistic upper limit for memory that can be dedicated to Geneious is 1GB on those machines. With that said, there are things that can be done to improve the performance of Geneious even on limited machines:
1. You can allocate more RAM to Geneious under the Tools→Preferences→General tab. However ensure you leave enough for your operating system to function efficiently.
2. Check how much memory Geneious is actually using in the Memory Usage Bar under the Sources panel. If Geneious seems to be using a lot of memory even when you are not running analyses, you may need to check that the Indexer isn’t running, or force a garbage collection to free up unused memory by clicking on the memory bar. See “Why does Geneious appear to be using lots of memory when I’m not running any analyses?”.
3. Check that you are using an appropriate algorithm or analysis for your dataset. See “Why is my alignment taking so long?” and other questions under the Geneious Functionality category.