Five and a half years ago, AMD launched its Athlon 64 processor lineup, extolling the benefits of 64-bit computing and what it’d mean for the future. It didn’t take Intel long to follow suit on the desktop. From there, the infrastructure—the operating systems and drivers—began falling into place to support more 64-bit software.
Today, 64-bit compatibility is almost a given. In fact, in the business space, where 64-bit computing has always been seen to have the most promise, applications have emerged that will only run in 64-bit. Even Small Business Server 2008, a relatively entry-level operating environment for businesses with up to 75 users, is now 64-bit-only due to its inclusion of Exchange Server 2007.
Why did Microsoft make the executive decision to launch its latest messaging platform exclusively in 64-bit trim? According to a blog post by Chris Mitchell in Microsoft’s Exchange Performance Engineering Team, the application uses 64-bit addressing to get its virtual hands on more system memory, preventing repeated trips back and forth to disk. In Chris’ example, an older version of Exchange might have access to 900 MB of a 32-bit server’s 4 GB ceiling. In a 4,000-user enterprise, that's 225 KB of RAM per user—not nearly enough for all of the messages, rules, calendar entries, and contacts in a typical mailbox. Moving to 64-bit and upgrading servers to 10s of gigabytes (Chris’ recommendation in that same 4,000-user business is 24 GB) softens the load on storage.
But desktops aren’t nearly as hard-up for memory, right? We expected 64-bit computing to trickle down from the enterprise, but gamers want to know: where is the benefit from this technology today?
Going To 64-Bit: Because You Can…
Enthusiasts running Socket AM2/AM2+ platforms commonly go with 2 GB or 4 GB memory kits. After all, even though DDR2 memory is cheap, 4 GB is still the enthusiast norm—8 GB is closer to workstation-class.
But when you buy a Core i7-based machine and step up to a triple-channel arrangement, it just doesn’t make sense to slide back the other direction and populate with three 1 GB modules. And so now you’re looking at 6 GB and a forced move to 64-bit computing if you want to actually use all of that memory.
…Or Because You Have To
Oh that’s right—I almost forgot. In case you've been living under a rock since AMD started preaching its 64-bit message, the fundamental limit on how much RAM a 32-bit operating system can see is 4 GB (2^32). Anything more simply won’t show up as installed memory.
Once you factor in device addressing, the magic number actually drops below 4 GB. That’s why it’s common for 32-bit systems with 4 GB to report 3 GB plus change in the Windows Device Manager. It’s not a Windows problem, though. Rather, that’s just how x86 architecture works.
Workarounds for reclaiming that lost memory have been introduced, of course. Intel’s Physical Address Extensions enabled 36-bit physical address tables, which did help in server environments by upping maximum memory size to 64 GB. However, according to a presentation given by Chuck Walbourn, software design engineer in Microsoft’s XNA Developer Connection at Gamefest 2008, PAE never really worked the way it should in with desktop operating systems, which would have needed to map the 4 GB virtual address space into the greater physical space. Drivers were the main problem, he said. They had application compatibility problems, assuming they always had 32-bits with which to work, not 36.
In addition to the 32-bit physical address lines, you’re also limited to 32-bits of virtual address space. Because one bit is reserved for shared kernel memory (used by all processes and the operating system), individual applications only have access to a maximum of 2 GB of private address space. Suddenly, you’re facing limitations that just might have a more profound impact on a desktop machine. Could taking the 64-bit plunge today actually make a significant difference in your gaming experience? That’s what we’ve set out to explore.
- Introduction
- More Memory, Please
- A Pair Of 64-Bit Gaming Case Studies
- Tom's Hardware Sits Down With Chuck Walbourn
- Tell Me More About Hacking LAA
- Setting Up An In-Depth Look At Performance
- Crysis: Testing Native 64-Bit Performance
- World In Conflict: Adding Frame Rate Minimums
- Far Cry 2
- Grand Theft Auto 4
- Left 4 Dead
- 3DMark Vantage
- Conclusion

But only if that game was DRM free and didn't want me to go on-line to activate it. I've got better things to do these days as most of the games suck.
I dont expect this to change radically for a while yet. Maybe 2010/2011 will be the time of 64bit?
Dont get me wrong I'm all for the full migration to 64bit but some folks need to catch a little perspective maybe?
Dont get me wrong I'm all for the full migration to 64bit but some folks need to catch a little perspective maybe?
indeed 64-bit needs a bit more time. alot of people still use 32 bit however and dont plan to move to 64bit any time soon this is why programmers choose not to script 32-bit af of now because that group is to large. however in the upcomming two years as when windows 7 will launch people will more steadly migrate to 64bit operating systems and by 2011 2012 64bit should be the standard programmers code for. dont worry to much about it this means AMD was way ahead with its first 64-bit cpu's
So what if some games claim to have some 64bit optimisations, that doesn't mean the company was actually any good at implementing them, nor tested them effectively enough to know if they make that much of a difference.
64bit gaming is currently pointless, a bit like this test.
The author discusses all the benefits of 64-bit computing. We are told these include increased content (visual details for example) and better stability for long sessions/ RAM heavy games.
Then the article goes completely tits up (THG style) and starts discussing FPS differences between 32-bit and 64-bit. Did I miss something or has lost the plot somewhere along the way...
The 64-bit extensions AMD introduced are a kludge on-top of a kludge on-top of a... , etc., etc.!! They are purely about addressing more RAM (vs. greater performance from wider data pathways/ bigger register banks in a "from scratch" 64-bit Instruction Set Architecture). It is a known fact that the C2D CPUs can only "glob" x86 instructions and not x64 bit instructions - so they may in fact run 64-bit code slightly slower.
@andrazz you also can only compare Vista 32-bit vs. Vista 64-bit and Windows XP 32-bit vs. Windows XP 64-bit!! Any other comparisons will apples vs. oranges...
Bob
Now I'm using Vista 64bit, Q6600/4gig ram/8800gtx, the 64bit games do seem faster than their 32bit counterpart to me at least.
Perhaps just because the OS has the extra Ram allocation to free up HDD Paging. Either way it does the job.
You mentioned it in depth and how to do it etc, but didnt show anything that would show the difference in performance between them.
Would be nice to see if enabling that setting will increase any FPS or if it is just used for stability.
Bob
The best benchmarks will be scientific A.K.A., math libraries Like BLAS and FFT. Other area will be databases and GIMPs.
Also seeing that there are newer registers in the 64 bit world, explicitly using those registers will give a benefit w.r.t. speed and I am not sure if newer compilers (64 bit) are using those in an otimum way.
Colin
In a 32bit environment, video ram counts against the >4 GB wall. Running two 1GB video cards will drop your available ram to >2GB. I can imagine this bottle-necking gaming rigs running Vista. I cannot imagine trying to save 200$ on a new rig, by skimping on the OS and ram...
Quad-core and 64 bit IS a requirement, and with the absurdly low prices of ram and computer gear in general, why do people insist on being cyber-luddites?
Enjoy,
S*D
it called ramdrive. did sort of hdd apartition in the RAM. it could be interesting to see it these days or maybe something similar is out already
at least it is posible to run without virtual memory if you have 4GB+ ram.
i found only video editing tools demanding some virtual memo so far.