I want to program Arduino boards with the SAM D21, but the compile time is much longer than with ATMEGA328 boards I used before, more than 30 seconds now. My laptop is a Dell Vostro 1710 with Windows XP and Intel core Duo. I have to buy a new laptop anyway, but I don’t want to spend too much money. Which computer is minimal required, a Intel Celeron, i3, i5 or more?
The compile time is long at the first time because you have to compile all the core. Once this is done, all other compilation should take less time. (You have to recompile the core each time the IDE is launched I think). Did you notice a difference between the first compilation and next ones?
AloyseTech:
The compile time is long at the first time because you have to compile all the core. Once this is done, all other compilation should take less time. (You have to recompile the core each time the IDE is launched I think). Did you notice a difference between the first compilation and next ones?
There was nothing to panic. 
For small sketches, compiling the first time takes 25s ... 40s, the second time 8s ... 15s. No big difference with with the ATmega328.
What would be the complile time for a Intel i5 laptop?
Since you are buying a new laptop you might want to look into a SSD rather than a mechanical drive. Compilation is disk-intensive and a faster processor won't gain you much.
New laptops these days often come with a 1TB disk drive, much more than is needed for arduino development or for that matter anything but mass quantities of video files. Replace it with a 128 or 256 GB SSD. The drive together with a file transfer cable runs less than $100 these days. I did this a few years ago for both my desktop and laptop and as a bonus the old 1TB drive and a $30 case make a nice file backup unit.
SurfingDude:
Since you are buying a new laptop you might want to look into a SSD rather than a mechanical drive. Compilation is disk-intensive and a faster processor won't gain you much.New laptops these days often come with a 1TB disk drive, much more than is needed for arduino development or for that matter anything but mass quantities of video files. Replace it with a 128 or 256 GB SSD. The drive together with a file transfer cable runs less than $100 these days. I did this a few years ago for both my desktop and laptop and as a bonus the old 1TB drive and a $30 case make a nice file backup unit.
I will take this into account when bying a new laptop, thanks 
Some time ago, initial work was done on a multi-process build, where multiple instances of gcc would run in parallel. It's currently languishing in this "parallel" branch on github, which is now many commits behind the master branch. 
In theory, this could dramatically speed up those slow first compile times, at least on computers with a dual or quad (or more) core processor, with enough RAM and fast enough disk to support multiple compile jobs.
I noticed that the system specifications of your computer is a bit low, specifically it's on Win XP. Microsoft doesn't support Win XP operating system anymore. If you are planning to upgrade the operating system of your computer, that's a good option but if you wanted to have a new system, I suggest you buy laptop that has enough memory and good good graphics. Might as well check Most Reliable Laptops 2022 - LaptopRunner.com for some recommendations. Good Luck!
SSD wil definatly be an asset ... they seem a bit expensive at first but WAY usefull when looking into
$ to speed upgrade ( on new computers .... you can't make a tutle faster if it wears running shoes )
I would personally not go any lower than an i5, but thats just me.
I wanted a new laptop specifically for on-site programming. This would include air travel to the location. My present laptop is too heavy and too big to travel with conveniently.
I did some study and purchased a Lenovo Yoga 11e for only $300 on Amazon.. This has a Celeron processor and a 128 Gb SSD. After an upgrade to 8 Gb of memory it is fine for use with Atmel 7 and the Arduino IDE.
Plus. Smallish, very tough, adequate performance for programming, fast file operation with the SSD. Handles internet etc just fine. Very portable.
Minus. Quite heavy for its size - which is because it is so solidly built. Could be faster but an OK compromise.
Takes some time and work to upgrade and fine tune the installed operating system.
At first I thought this unit would not be man enough for the job but with more use I am happy with it.
I have a Lenovo W530 (W for workstation) with quad, or maybe octal core, i7 processor, and upgraded memory. It's very fast. 32GD SSD drive for fast startup, 1TB drive for storing lots of files. Designing PCBs in Eagle works okay with 15" screen, also large enough to have 2 copies of the IDE open so I can cut & paste between projects, or have the serial monitor open while I make code changes and download and monitor the result.
W540 might be latest model. I don't like the number pad on the keypad that moves the regular alphanumeric stuff shift left and off center from the sceen. Many (most?) 15" & 17" models do that. I also don't like the Chiclet style keyboards that many (most?) laptops seem to have now.
Try various computers to be happy but you really do not need a very powerful machine to work with Arduino code. Anything that can run a spreadsheet can run Arduino.
As AloyseTech said, the biggest change you can make is to use a different compiler. The Arduino IDE recompiles the whole code every time you use it. Atmel Studio 7 with the VMicro add-in only recompiles the changes. The code recompiles so fast that if you look away you can miss the process. I do not know whether this is the basic Studio 7 process or whether it is a result of the VMicro add-in.
Atmel Studio takes a long time to load but you only do that once. The first compilation takes a noticeably longer time. Later compilations are fast. That is 507 lines of code with a 1.8 G Celeron processor, 8 G of RAM and an SSD.
Brian_M:
As AloyseTech said, the biggest change you can make is to use a different compiler. The Arduino IDE recompiles the whole code every time you use it.
I said that the whole code is compiled once, not everytime. After the first compilation, the compiler only works on changed files.
AT, that is what I tried to say.
"As AloyseTech said, the biggest change you can make is to use a different compiler. The Arduino IDE recompiles the whole code every time you use it. Atmel Studio 7 with the VMicro add-in only recompiles the changes."
At least my version of Arduino seems to recompile the code every time I use it. It is quite slow. Using Studio 7 the compile is very fast (after the first time of use) and according to other reports this is because Studio 7 (or Studio 7 plus the VMicro add-in) only compiles the changes in the code. If the Arduino IDE also only compiles changes in the code it is much slower than Studio 7.
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I suggest you buy laptop that has enough memory and amazing graphics. I can recommend: Skylake (6th generation) Intel Core i7-6700QH processor wth up to 2.6 GHz and 3.5GHz on turbo boost, and 12GB system memory. You can as well check Lenovo Y700 Gaming Laptop Review - Laptop Verge, They have reviewed the lenovo y700 ideapad, which I have been using for close two years now.