3DMark 11
3DMark 11 is the latest version of this hugely popular synthetic benchmark. Making use of DX11 features such as tessellation, compute shaders and multi-threading, it provides modern-day results and is available as a free download.
The ASUS GTX 560 TOP slots in alongside a regular GTX 560 Ti, which makes sense once you appreciate the whole frequency/architecture angle.
Manually reducing the TOP's speeds to match a GTX 560 Ti's we see that it's just over 10 per cent slower. Tellingly, GTX 560 is miles ahead of the GTX 550 Ti.