How do i connect 4 DVI monitors to my MacBook Pro 15 inch early 2013?
Hmmm, this is an interesting question because the monitors you want to connect to are only capable of a maximum resolution of 1280 x 1024.

Apple's official stance

Officially these MBPs can support up to one HDMI display (at 1920x1080 pixels) while simultaneously connected to a Thunderbolt display (at 2560x1600 pixels), OR being connected to two Thunderbolt displays (both at 2560x1600 pixels).

Unofficial real-life scenarios

However, unofficially you can exceed this. I'm not aware of anyone who has tried connecting these MBPs to four displays at a lower resolution. What I have seen instead are the following scenarios with the mid-2012 Retina MacBook Pro which uses the exact same setup (NVIDIA GeForce GT 650M and Intel HD Graphics 4000):


safely connecting two 27" Thunderbolt displays each at 2560x1600 pixels while also using the built-in display. Doing this results in about a 23% increase in the MBP's fan speed, but with no long-term damage/problems.
safely using a single Thunderbolt display at higher resolutions (e.g. 3440x1440) with the MBP in clamshell mode without any problems whatsoever.
safely using two 27" iMacs in Target Display Mode (one using a Thunderbolt connection and the other a Thunderbolt/DisplayPort connection) without any problems (both in and out of clamshell mode).
safely using a single Thunderbolt display at higher resolutions (e.g. 3440x1440) while also using the built-in display. This seems to work okay, although the fans do spin about 30% faster. This is probably the limit of how much I'd recommend pushing things at these resolutions.


I've also seen users connect three external displays while in clamshell mode. However, this resulted in the MBP's fans spinning at more than double their usual speed when watching videos etc. Not something I would recommend.

Your unique scenario

It's not clear from your question whether you were wanting to use the MBP in clamshell mode. If I assume you do, then you're in a situation where you want to use four external displays with a total of 5,242,880 pixels which is less than the official combinations supported by Apple. So the only problem you're likely to face is how you'd physically do this?

I see the following solutions for connecting four of these particular displays:


Option 1 - Use a combination of two Thunderbolt > DVI adapters, one HDMI > DVI adapter, one USB > DVI adapter.
Option 2 - Use a combination of two Thunderbolt > VGA adapters, one HDMI > VGA adapter, one USB > VGA adapter.
Option 3 - A combination of options 1 &amp; 2 above (i.e. you could use one Thunderbolt > DVI adapter and one Thunderbolt > VGA adapter, and either of the HDMI or USB adapter options.
Option 4 - Utilise two USB adapters and two Thunderbolt adapters.
Option 5 - Utilise two USB adapters and one Thunderbolt adapter and one HDMI adapter.


Personally I would not recommend Option 4 or Option 5. Not only do these options use up your USB ports, they also double up on using an adapter that will have limitations. By limitations I mean the bandwidth provided by your USB ports will not work well with many games or anything that is graphics intensive. However, if you're just using MS Office or doing some basic web browsing, you should be fine.

Below are some links that may be useful:


Thunderbolt to DVI
Thunderbolt to VGA
HDMI to DVI
HDMI to VGA
NewerTech USB 3.0/2.0 to DVI, VGA, HDMI 
Kensington Usb Multi Display Video Adapter 


Finally, you may find the Matrox TripleHead2Go DP worth considering.