What is the best possible CPU for an AM2 Mainboard / Best Upgrade for an AMD Athlon 64 X2 3600+?

[Real_Smoky]

Budget (including currency): TBD

Country: Germany

Games, programs or workloads that it will be used for: Various

Other details: 

I have a weird AM2 mainboard that is an industry mainboard, but I use it as a testbench for GPUs (not really benchmarking, just seeing if they turn on and display). It uses only a 20 pin PSU connector (not 24, and also has no additional 4 or 8 pins for the CPU). The socket says AM2 (NOT AM2+). Currently, there is an AMD Athlon 64 X2 3600+ in it that works flawlessly. But is there any 4 core CPU that will work?

Thanks! 

 

[jaslion]

If it's just for gpu testing why the need for an upgrade? As for cpu compatibility we need to know the board. Some boards are locked to just athlon 64's especially the first am2 ones had that chance.

[Real_Smoky]

1 hour ago, jaslion said:

If it's just for gpu testing why the need for an upgrade? As for cpu compatibility we need to know the board. Some boards are locked to just athlon 64's especially the first am2 ones had that chance.

When I get to it, I will turn it on and see what Windows says, but on the board, it says Endat k802 rev a7.