My brain is fried as of now. Bong! I think even if you add a USB controller and have it hooked up to an existing controller, then the problem still will exist for bandwidth and power. Just my opinion but probably so the way it looks.
 
If you have 2 controllers on that laptop, then no problem. (although explained down below one controller you may not have access to to use anyway.)
 

http://www.tomshardware.c...ase-bandwidth-windows7

http://technet.microsoft..../library/cc772242.aspx

http://www.faultwire.com/...th-Exceeded-*1553.html

http://en.wikipedia.org/wiki/USB
 
Bong!
That is all I can gather from this. Adding a controller on top of an existing controller will not solve the problem if there is one using USB devices. Break time.
 
I had the Wiki page up for USB hubs where more was explained but then I did not get the link copied but that can be clicked on with the wikilink that is there already by reading the page.
 
I am thinking that since the OS takes 20% of the bandwidth for whatever, and the RME Babyface takes 16% which leaves only 64% left of the bandwidth of the controller that a device like a camera or also perhaps an external hard drive that needs up to 70% of the bandwidth, then it would not work on the same controller. It would be short by 6%.
But in that laptop you also have a webcam and skype whatever and perhaps you have two controllers but those probably run off of a USB hub controller also. So also then depending, if they take more than 10% along with the system reserved by the OS adds up to more than 30%, then a 70% device perhaps like an external harddisk or camera, then that would also not work depending again on how much bandwidth (or power) those devices use. Perhaps you can disable those in Device Manager, but then again do you have access to the controller and perhaps you would not have access to it like the other 3 ports on the laptop. Again then there would be that problem with the laptop and depending on the audio/interface, you could not run the external harddisk and the audio/interface on the same controller. I do not know, perhaps that is something that can be searched for on the Internet also before shelling out any money for anything then.
 
 

5400 rpm drives in laptops are standard because the primary design imperative is battery life, and the secondary imperative is cooling. Slower drives run cooler and use less power, and most people buying laptops are getting machines that are already way more powerful than they will ever use for office apps and web surfing. A slow drive makes no difference for the masses of laptop users, and extra hour of battery life will make or break the machine in the market. Putting a hot drive in a laptop that is not spec'ed for that may lead to heat problems.
 
If you want to fully utilize a fast external drive, there is the possibility of a bottleneck on USB 2. Fast SATA drives with large buffers mounted in external enclosures may actually be able to move data faster than USB 2 can handle. eSATA ports are rare if not non-existent in laptops, so USB 3 may be the fastest you can practically feed the drive. Be aware that many of the actual hard drives in external drive boxes are not super fast and not a few are "green" by design meaning either the controller in the enclosure, or the drive itself will power down to save energy which may screw up real time data transfer if it has to rev up during a slow cycle to accept your data.

I was just thinking (guessing) that perhaps the audio/interface would also use and need more bandwidth depending on how many channels are being recorded or played at one time. Like with my RME Babyface, the 16% would go up higher and higher if all inputs were being used - just guessing and I don't know for sure.
 
?? Seems reasonable though that bandwidth depends on what is being done on the USB port.
 

Thanks for the input guys. So you are obviously aware of these speed/heat issues. The reasons I wanted to get a laptop was convenience, portability, plus many of the laptops have five times the speed in CPU and RAM than my current desktop PC does. Another reason I want a laptop is that it's quieter than my desktop, the fan noise from my desktop gets in the background of vocal tracks, so I'd really rather not get another desktop.
 
So despite the quick speed of a laptop such as the ASUS I'm looking at, I may be severely restricted by the USB bottle neck if I have to use the 5400RPM drive with an external 7200RPM?? That sucks!  Is there any other possible solution? I'm wondering how much of an overheating risk it is to install a 7200RPM to replace the original that comes with the laptop? 
 
I am aware of the "green" externals, they are a pain in the butt. I burned one out using it to play my Sonar projects, and it does interfere with audio play. I almost lost all my data, luckily I had it double backed up on another drive. They are not made to take the abuse, that's for sure. I would definitely need to go with USB 3 instead of ver 2, though I don't know enough about them to know how much more data can be moved through a USB 3 compared to a USB 2. Still don't like the fact that it will be restricted, because let's face it, if the USB is going to only go so fast, what's the point in getting a machine that is quad core processor with 8GB RAM if it's not going to be put to it's full use??
 
I'd like to hear from some others here who maybe already have a laptop setup and have tested these scenarios. I would appreciate any suggestions. Before I go out and spend $$$ on a laptop I'd like to know that it's not going to choke if I need to run a big audio project file, and I'd like to know what might be my absolute best setup scenario that will utilize my laptop's speed to the fullest.

USB 3.0 is theoretically much much faster than USB 2.0, and is probably fast enough to saturate the write capacity of a 7200 rpm drive in actual real world use. In other words unless you are feeding an SSD via USB 3.0, the bottleneck is likely to be your 7200 rpm drive's sustained write speed rather than the USB pipe.
 
http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

That is an encouraging thread, thanks for the link, much appreciated, although there was some dispute in the posts that followed further down. If USB 3 is that fast then I should have no problem as long as I don't get an external that is "green".  That shutdown feature is definitely annoying to say the least, kinda like how my DVR drive operates when I'm watching a video disc and changing scenes, same thing happens. Like the DVR drive has to establish an initial read on the same disc over and over. (There's gotta be a work around for that, I just don't know it I guess!)
 
I am still curious as to what extent, if any, replacing the internal 5400RPM HDD with a 7200RPM would cause overheating issues. How much hotter does the 7200RPM run that it would make that much difference? I don't have a clue as to the answer to that, just curious if anyone thinks it's worth a try.