In response to this article posted at ZDNet a couple of days ago (we posted about it as well), Tim Sweeney, the man at Epic Games posted the following on Slashdot news comments:

Intel's claims are wholly out of touch with reality. On a daily basis we're running into the Windows 2GB barrier with our next-generation content development and preprocessing tools.

If cost-effective, backwards-compatible 64-bit CPU's were available today, we'd buy them today. We need them today. It looks like we'll get them in April.
Any claim that "4GB is enough" or that address windowing extensions are a viable solution are just plain nuts. Do people really think programmers will re-adopt early 1990's bank-swapping technology?

Many of these upcoming Opteron motherboards have 16 DIMM slots; you can fill them with 8GB of RAM for $800 at today's prices. This platform is going to be a godsend for anybody running serious workstation apps. It will beat other 64-bit workstation platforms (SPARC/PA-RISC/Itanium) in price/performance by a factor of 4X or more. The days of $4000 workstation and server CPU's are over, and those of $1000 CPU's are numbered.

Read the rest here.