I want to get a laptop to record with my roland studio capture. All mixing etc will be done on PC. So I just need it to keep up with 12 simultaneous tracks. I'm thinking 6-8 gigs RAM. Any recommendations? 
Thanks
Steve

Few things to consider when you tracking more than 8 tracks simultaeously:
 
1. Make sure you use SSD instead of HDD. In laptop, HDD is VERY slow, it will lag your system and gives you high latency issue.
2. Make sure the USB port used to connect audio interface is at least USB 2.0 , and not chainned with other USB devices.
 
I have never recorded 12 simultaneous audio tracks with laptop (I use PC for more than 4 simultaneous tracking), but even my old core2duo with 8GB DDR2 laptop can easily record 4 simultaneous 24 / 44.1 easily. So I bealieve any new processor (i5 and above) is not a problem.

I would think any modern laptop should be quite capable of recording 12 tracks of audio, especially if you are not needing any real-time monitoring in the box, or any real-time FX during the tracking session.
 
The previous advice is very important, as most laptops come with slow spinning 5400RPM HDDs.  If you are only going to get one internal drive, recommend opting for the largest SSD you can afford.  Otherwise, if you can get a laptop with a 2nd internal drive bay, get that equipped with a large 7200RPM HDD for audio, and leave the 5400RPM drive for the system partition.

James Argo
Few things to consider when you tracking more than 8 tracks simultaeously:
 
1. Make sure you use SSD instead of HDD. In laptop, HDD is VERY slow, it will lag your system and gives you high latency issue.
2. Make sure the USB port used to connect audio interface is at least USB 2.0 , and not chainned with other USB devices.
 
I have never recorded 12 simultaneous audio tracks with laptop (I use PC for more than 4 simultaneous tracking), but even my old core2duo with 8GB DDR2 laptop can easily record 4 simultaneous 24 / 44.1 easily. So I bealieve any new processor (i5 and above) is not a problem.

+1 to this.
 
If all you're doing is tracking, then I/O bottlenecks are what you need to avoid. So (i) a fast hard disk (SSD), and (ii) A decent USB 2.0 interface, preferably with nothing else sharing it.
 
For the USB side, check the specs of the laptop to see if the USB interfaces are separate or not. Most laptops offer more than one USB slot, but with some cheaper laptops these are basically a USB hub rather than separate ports. It might not be an issue, but you're better off with dedicated ports.
 
CPU speed should not really be an issue. For what it's worth, back when I was using Pro Audio 7 and a Yamaha DSP Factory card, I could record 16 simultaneous tracks on a 166Mhz Pentium with 64MB of RAM on to an old IDE hard disk. Although it was a PCI card rather than USB, a USB 2.0 bus runs more than twice as fast as the CPU on that machine. When I upgraded to an Athlon 750Mhz and an extra DSP Factory card, I could comfortably record 24 simultaneous tracks (it struggled a bit with more than 24 tracks due to the hard disk speed, but it could do 32 tracks albeit a bit hit and miss).
 
In saying that, I'd avoid Intel Atom based laptops. I've got an Atom based 1.6Ghz netbook that struggles with anything more than 2 tracks. My 2Ghz core duo however can cope with 8 tracks comfortably (I've not tried more).
 

I do this a lot with an old laptop.

It has a large hd 7200 rpm with some kind of front side cache.

I routinely record 16 tracks at 48k samples per second and the drive is never pushed above 2% write capacity as reported by rme digicheck.

Windows button + x... Presentation mode can help. I often turn on the laptop and record silence for some hours before the gig to make sure no windows tasks will get in the way during the show.

Windows updates can ruin things.

Using the laptop only for sessions once in a while means that all those windows tasks are hungry to trigger. I find it easier to leave the laptop on overnight the day before I need it than to disable tons of stuff that could matter.

I don't use sonar which stops recording at a dropout event. I use digicheck or ardour/mixbus on Linux Ubuntu studio. Both of these keep recording through machine issues and you can sort it out later.

Make sure to save between sets. Dupe copies of the recording at the show for the band. That way they will try themselves and appreciate your work all the more.

My laptop has 4 gb ram.

I can overheat it by running spectral analysers on all sixteen tracks while recording in the summer.

Thanks for your input, everybody!

I routinely record 32 mono tracks at 48k/24-bit with a Lenovo T400 laptop. It's a Core 2Duo at around 2.4GHZ.
The destination drive is a 7200 RPM 500GB Seagate drive in a caddy that replaced the DVD drive.
Capture software is Waves Tracks Live.

Audio interfaces have been Behringer X32 USB, Echo AudioFire FireWire, and Dante Virtual Soundcard. All successful.

gswitz

I often turn on the laptop and record silence for some hours before the gig to make sure no windows tasks will get in the way during the show.

Windows updates can ruin things.

Using the laptop only for sessions once in a while means that all those windows tasks are hungry to trigger. I find it easier to leave the laptop on overnight the day before I need it than to disable tons of stuff that could matter.

All good advice here.  Goes along with the general mainstream advice to always optimize your PC for audio by reducing or eliminating most startup and scheduled tasks.  No need for extra tasks running in the background that may pop up and bite you in the middle of a recording session.
 
Also make sure that you are running on AC power if possible and use the high performance power settings in Windows, by disabling all power saving and CPU throttling features.

If you're just tracking audio, you can work at higher latency settings.
That makes the machine and configuration less critical.
 
Where the "wheels start to fall off" with most laptops is when you're trying to run heavy loads at smallest ASIO buffer sizes.

Jim Roseberry
If you're just tracking audio, you can work at higher latency settings.
That makes the machine and configuration less critical.
 
Where the "wheels start to fall off" with most laptops is when you're trying to run heavy loads at smallest ASIO buffer sizes.

What Jim says is true. When I'm recording out, the buffers are maxed out. Any routing to mains or monitors is through the interface only.