These stickers will not have any affect on performance nor will they be affected by the heat inside the system. Unbuffered DDR memory is targeted at the consumer or home computer market. These are for system boards that will only support up to 2GB total memory. Registered DDR memory is targeted at the commercial market and its server and workstation environments. Registered DDR will be used in systems that will support up to 4GB total memory.
Registered modules are more expensive than Unbuffered modules.
The type supported would depend upon the system. Currently, the AMD-760 chipset will support both Registered and Unbuffered DIMMs. Future chipsets may vary in what they will support. Be sure to check the documentation that came with your system to determine which type of memory it will properly support. It tells the system s BIOS what the specifications and settings of the memory module are.