Hi. The 1300Mbit/s is just a theoretical rate of the standard... doesn't really mean it would actually work in reality. You can check the following two reviews for this card (I also have it and I'm quite happy with it, but haven't tested the throughput as I'm more interested in latency and reliability):
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http://www.trustedreviews.com/asus-pce-a...
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http://www.digitalcitizen.life/reviewing-...
It also depends if your swisscom router is an AC router or not and what it's really set to. I have the ASUS RT-AC66U and they work very well together. Try looking at the router settings to ensure it's properly configured. I would also test the card against a verified AC access point (I mean one that you know is able to support higher speeds) so you can rule out the wifi router. Hope it helps.