Netgear wndr3700 with dd-wrt or pfsense custom built router

The alix 2d19 bundle for 200 bucks has a motherboard that contains a 500mhz cpu. However, my netgear wndr3700 has more cpu processing power with 680mhz, and I bought it way back in 2010 for 180 bucks.  

" ok chronofusion but buying the 2d19 bundle and installing pfsense on it will allow it to deliver your internet and networking coherent features better and faster than your netgear router with netgear's firmwares although the alix system's cpu is slower than your wndr3700's."

ok  prove it. Sincerely, I'm all open eyes.  I thought about replacing netgear's firmware with dd-wrt but haven't seen a real need to yet.  

Thus WHICH option is better performing?  The Alix 2d19 bundle with installing pfsense vs wndr3700 stock or dd-wrt firmware.  Go.

Use the Alix for the PFSense Box, then use your wndr3700 as the wireless access point/switch

Pardon me, but what benefit would that give me at my current situation of having that netgear router with stock firmware ONLY + motorola sb6120 modem with 80mbps down/8mbps up with Comcast versus alix with pfsense+the netgear as an AP/switch?

Does that type of hardware combination yield any noticeable benefit such as better minimum worst-case-scenario bandwidth/performance when more than one device is playing online games and/or downloading movie files ( for example)?  It is simply a matter of it would then be " two men working to manage the load" instead of one?"  Also how can I determine if my router is even being breaking a sweat with two pc's downloading videos at the same time?

Or is it just more simple and even costing the same to just buy a new router ( ac1750 range of class router like asus r68u for example or r66u, or netgear's closest equal) since that's 200 bucks with what seems to be equal hardware horsepower rather than buying the Alix box and adding the 1 or 2 GB small pcie card into it and combining it with the wndr3700?

This is semi off topic but  I played with dd-wrt firmware with my old linksys wrt54g router back in the day some but I really didn't know much of what I was doing and knew not well how to test the performance improvement.  I mention this in relation to possibly putting dd-wrt firmware into the netgear router, but I'm kind of afraid that i'll brick it.

Sorry if I seem to be thinking too much.  I'm analytical.  It's in my nature.

The biggest difference I've noticed between standard consumer routers and pfsense in terms of network performance is that pfsense can handle much more connections. Before I used pfsense if I tried to download a bunch of torrents at once my connection would crash within minutes, with pfsense I have never had a problem.

Awesome.  So thus with pfsense dedicate physical alix d19 bundle+ my router as the wireless, minimum performance with multitasking on the net is improved.  That's good enough for me. Done.