Quote: Original post by Codeka
in particular PAE is only available on Server versions of Windows, not on workstation versions

PAE is available in 2000 Professional and Windows XP. However, the OS is limited to 4GB of physical ram. That doesn't necessarily defeat the purpose of PAE, but it does rather significantly reduce the effectiveness of using PAE. It's only on Windows Server 2003 Enterprise edition and above that PAE really begins to pay off, with the ability to handle 32GB of ram and above.

Quote: Original post by Codeka
Also, the "Server" editions of Windows (since Windows Server 2008 R2) no longer come in 32-bit "flavour" and I presume that consumer versions of Windows will probably follow suit as well (maybe not in the next version, but definitely "soon").

But running 32-bit applications on 64-bit versions of Windows is still possible, and unless you actually need what 64-bit provides (bigger address space, mostly) there's not really any need to write 64-bit applications.

Whether your program will be faster compiled as 64-bit is a difficult thing to predict. I would say that in general the additional memory requirements (because all your pointers have doubled in size) results in a net loss of performance (particularly when your algorithms/data no longer fit in L1/L2 cache). Here's an interesting blog post on why Visual Studio doesn't have a 64-bit version.

Interesting info I hadn't seen that about why Microsoft is so slow to go 64-bits with Visual Studio but the response seems pretty lame considering Office 2010 is already coming in 64-bit versions. Not to mention that anyone that has tried the VS2010 beta knows that rewriting the entire GUI in managed code(WPF) totally kills the performance anyways. Pretty laggy running in a virtual machine unlike prior versions.
Oh well at least we have the 64-bit C++ VS compiler command line tools.

Well since everyone already did a good job of covering the advantages from a technical and programming viewpoint I"d add what the advantage is for most end-users:
"Even systems with as little as 2GB can be prevented from having all their memory usable under 32-bit Windows because of chipsets that aggressively reserve memory regions for devices. Our shared family computer, which we purchased only a few months ago from a major OEM, reports that only 1.97GB of the 2GB installed is available:
"
I've seen cases where people with high-end SLI videocards that eat up a 1GB of ram running on 32-bit versions of Windows ending up with as little as 1.5GB of ram they could use on their PC even though they had 4GB or more installed!
So I'd say that happens to you your going to want 64-bit Windows to reclaim that lost memory.

Quote: Original post by daviangel
Interesting info I hadn't seen that about why Microsoft is so slow to go 64-bits with Visual Studio but the response seems pretty lame considering Office 2010 is already coming in 64-bit versions.

He did mentioned that. The difference is that there's arguments for why Excel (say) would benefit from the larger address space, while there's no such argument for Visual Studio.