New router

I don't really see how this is especially relevant to iMacs but....
If you want to max wireless speed for your iMac get a 802.11n compliant router. If you only want fast wired speeds just get a gigabit ethernet router.

 

I'm no expert, but I don't think replacing your router will give you faster internet speed for your iMac, because the "g" router you've got already gives the iMac a wireless connection that is almost certainly faster than your internet connection. In other words, it's probably your internet connection speed (determined by your ISP) that is the bottleneck.

What type and how fast is your internet connection? I've got FIOS fiber optic at 25 Mbps -- a lot better than most people have -- and that's still slower than the 30 Mbps to 54 Mbps you should be getting with your existing router! If you've got DSL then your internet connection is way slower than the wireless "g" speeds.

Perhaps your devices are not getting good (fast) wireless connections to your existing router for some reason? Can you verify what wireless speeds you're getting? In this case I don't know if a new "n" router would help or not.

Now, if you wanted to transfer lots of large files between devices within your wireless network (wirelessly between the iMac and the PC, for example), then upgrading to an "n" router can increase that speed noticeably.

Regards,
Brian33

 

IMHO it's almost a no brainer, get the Apple Airport Extreme. You can even find them in Apple's refurbished store for a nice discount.

 

No brainer, get the WNDR3700 or even the WNR3500L.

 

I had quite a few problems getting a new router that my devices could maintain a connection to. Dropped connections is a big issue, it was for me and from the amount of posts I've read when trying to diagnose my issues, it looks as though it's a problem for a lot of users.

All the main brands of router are effected to varying degrees and there's lots of reasons that cause or contribute to the cause of dropped connections.

My Linksys WRT54GS was ok for a few years but I think that the increase in wireless devices in my local region, as in mine and my neighbours houses, decreased it performance and ability to keep connections.

After trying a few different routers, I opted for an Apple Airport Extreme Base Station which, so far, has been faultless.

 

I'd save your money. Looks like your ISP is the problem. Time Warner is well known for inconsistent download speeds.

The Linksys is probably doing its job just fine. In the case of bad WiFi reception, you could try running a patch cable to see if your speed improves, but with a 2-12Mbps internet connection speed, you're unlikely to notice any change. Network transfers is where a bad WiFi connection will kill you.

I'd change the ISP (if you can) before I'd change the router. There's no use in throwing away good hardware.