The Galaxy GeForce GT 220 1GB GDDR3
The Galaxy GeForce GT 220 comes clocked at 660Mhz at the core, 1436MHz at the shaders and 1600Mhz DDR at the memory. This is only slightly higher than NVIDIA's OEM card's reference clocks. Of the two cards on hand, the Galaxy GeForce GT 220 has the larger cooler, and so should perform better during the operating temperature test later. That aside, fan noise wasn't intrusive. To end, the Galaxy card also has a larger frame buffer size of 1GB.
The Palit GeForce GT 220 Sonic 512MB GDDR3
The Sonic moniker should tell you that this is an overclocked variant of the GeForce GT 220 from Palit and so the card comes with significantly higher clock speeds. The card is clocked 720MHz at the core, 1566MHz at the shaders and 1800MHz DDR at the memory - this is much higher than its Galaxy counterpart. However, it has a noticeably smaller cooler, and smaller frame buffer size of 'only' 512MB (though that should be more than adequate for its class).