Powering max7219 displays

Hello.
Can someone tell me how many max7219(picture below) displays arduino can power up and work with?
I want to use total 8 of them, will arduino manage to do it?
I tried to do with 2 and it worked perfectly(dont have 8 right now)
If its not possible, what kind of power supply should i use?
Thanks

An Arduino doesn't power anything.
An Arduino can control many more than 8 of those, so you'll be fine.
Give them power from your power supply, there is no reason at all to run it through the Arduino.

Think about it. 8 modules with 64 LEDs is 512 dots.
At power-up the MAX7219 defaults to Test mode that lights each dot with full intensity. This might be a massive current. e.g. 512 x 20mA is 1.024 Amp.

In practice you seldom light more than a quarter of the dots and probably with medium intensity.
The USB port on your PC might be able to manage a low brightness sparse display.
Much safer to use an external power supply.

David.