OH YEAH! Single upgrade modules with the capacities of up to "4 GB of RAM?" It has never been a better time to buy a quality made 4GB memory upgrade, at such a good value. PRO Memory Upgrade offers from 4GB DDR3 SO-DIMM modules to 4GB DDR2 desktop Fully Buffered (FB-DIMM) ECC Registered memory (RDIMM) upgrades just like Dell, HP and Apple install. Be sure to confirm your OS so you can run at 4 GB of RAM and beyond. 64-Bit Vista editions will allow for more than 4GBs. Servers and Apple Macs like the New Mac Pro will run awesomely!