We'll start this benchmark by assigning 512 MB of RAM to the Windows 7 guest OS. This is the minimum amount of RAM recommended by Parallels to run Windows 7 (64-bit). We thought it was a good idea to start our memory performance testing at below optimum levels, to determine how performance does or doesn't improve as memory is increased.
After setting the 512 MB RAM allotment, we ran each of our benchmarks using 1 CPU/Core. After the benchmarks were complete, we repeated the test using 2 and then 4 CPUs/Cores.
512 MB Memory Results
What we found was pretty much what we expected. Windows 7 was able to perform well, even though memory was below the recommended levels. In the Geekbench Overall, Integer, and Floating Point tests, we saw performance improve nicely as we threw additional CPUs/Cores at the tests. We saw the best scores when we made 4 CPUs/Cores available to Windows 7. The memory portion of Geekbench showed little change as CPUs/Cores were added, which is what we expected. However, the Geekbench Stream test, which measures memory bandwidth, showed a noticeable decline as we added CPUs/Cores to the mix. We saw the best Stream result with just a single CPU/core.
Our assumption is that the additional overhead of the virtual environment to use additional CPUs/Cores is what ate into the stream bandwidth performance. Even so, the improvement in the Integer and Floating Point tests with multiple CPUs/Cores is probably well worth the slight drop in Stream performance for most users.
Our CINEBENCH results also showed just about what we expected. Rendering, which uses the CPU to draw a complex image, improved as more CPUs/Cores were added to the mix. The OpenGL test uses the graphics card, so there were no noticeable changes as we added CPUs/Cores.