It shouldn't be as slow after you replace it. HOWEVER your wording may be telling me your network has other issues.
CNET has their best routers for 2016 out at http://www.cnet.com/topics/networking/best-networking-devices/
Amazon has best sellers at http://www.amazon.com/Best-Sellers-Computers-Accessories-Computer-Routers/zgbs/pc/300189 (I have the TP Link AC1900 from there)
Maybe I'd try that Dark Knight next time round?
I have an unfortunately slow network, but it's all that's available in my area. My router is pretty old, and I'd like to buy a new one: which routers are the best for a slow network?

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