Conclusion

After completing all our tests and analyzing the data we do not see a clear trend in any direction. Some benchmarks show small variations but those can be explained by inherent inaccuracy of those benchmarks. This is also supported by the results at different resolutions of the same test which often show a small performance increase in one resolution and a decrease in another - clear evidence for random variations.

However, this does also mean that SP1 will not hurt your graphics performance in any way. As a result of this article we can confirm Microsoft's documentation which does not promise any performance gains from the Service Pack 1 upgrade. The upgrade does bring many smaller improvements which will help with the general stability and security of your system, so we can recommend the upgrade, even though it might not be the worst idea to wait a bit and see if some unforseen problems show up.