Have you adjusted your buffer settings?
1 sec lag isn't necessarily the computers fault. You'll get a handful of M's from the ADDA but not that much. I'm guessing your buffer is set to 1096 for that much lag
To reiterate about lag when playing or recording - this is the important part.
Your computer specs don't really
directly affect the lag (or more accurately, latency) you might get. They do affect it indirectly though.
But assuming you're using the ASIO drivers for the interface and there are no weird hardware issues going on, the buffer size (along with sample rate) will determine how much latency you get when playing.
Basically the buffer is how many samples are buffered, so at 1024 sample buffer size, the drivers wait until 1024 samples have been gathered in the buffer before it processes them all at once and they are played out. So at 48kHz you have to wait until 1024 samples at 48 000 samples per second have been buffered, so roughly 1/48th of a second so around 20 milliseconds. The analog-to-digital and digital-to-analog conversions (ADDA mentioned above) add up a bunch, but it shouldn't be huge, maybe around 30 milliseconds total. I suspect that Amplitube is not using the correct ASIO drivers (it's not enough if they are installed, you need to configure your DAW or the standalone Amplitube software to use them) or there's something else wrong if you literally get a second of latency.
The reason we use buffers like this is that reading reading the sample, doing the processing and then outputting it takes some processing power, so compared to repeating that step for every sample separately it starts to take up massive amounts of processing time compared to doing it just once for a batch of 1024 samples (or more preferably something like 64 samples - a buffer size of 64 is pretty good in my experience). That's also where the computer specs do come into play, because a faster CPU (and maybe faster RAM to some small extent) will be able to handle smaller buffer sizes without dropping samples (sounds like nasty digital noise usually). So a slower CPU can't handle as many plugins or smaller buffer sizes compared to a faster one.
As a caveat I will mention that audio processing is pretty complicated in that there are a lot of small things that could go wrong, and if your laptop is old enough that it can't even run the operating system very well, it's possible that that could cause more lag I haven't encountered before. Similarly I don't think RAM speed makes a huge impact if you're just running Amplitube, but RAM size could in the case where the computer can't keep both the OS and Amplitube in the RAM at once and has to use the swap file, which might complicate things.
