hendrik Posted November 11, 2009 Share Posted November 11, 2009 Title of a fascinating article in UK's MicroMart magazine inspired by an article by Geoff Chappell. (http://www.geoffchappell.com/viewer.htm?doc=notes/windows/license/memory.htm) Apologies if this is old news to techies, but its news to me! Essentially it is argued that "32-bit editions of Windows Vista are limited to 4GB not because of any physical or technical constraint on 32-bit operating systems. The 32-bit editions of Windows Vista all contain code for using physical memory above 4GB. Microsoft just doesn’t license you to use that code". The amount of memory that MS allows is apparently returned by a function called ZwQueryLicenceValue. Chappell managed to hack this to return more memory in 32 bit Win (although only in Safe Mode). The author of the MM article has been trying to get a response from MS since August without success! If true this throws up a lot of questions. eg Memory manufacturers could be usefully selling DDR above 4GB to 32 bit Win users. 32 bit Win users could get the some of the benefit of 64 bit apps designed to access memory above 4GB. The biggie for FSX I suppose is would 32 bit users see the benefits of 64 bit Win 7 if they were able to access the extra memory. Expert comments welcomed! Link to comment Share on other sites More sharing options...
Russ White Posted November 11, 2009 Share Posted November 11, 2009 An operating system that is built on 32bit architecture can only use a 32bit string to reference any memory location. Which means a 32 bit memory address can only refer to a maximum of 4.2 billion unique locations, that equates to the 4GB address limit. Your question is really of moot point now mate as with Windows 7, all stand alone single user boxed versions ship with both 32 bit and 64 bit versions of the OS in the box on seperate DVD's. So you are not saving any money by sticking with 32 bit, the only real reason for not going to 64 bit in the past was lack of driver support, but in recent years 64 bit driver support is no longer an issue. Russ. Link to comment Share on other sites More sharing options...
Gurdy Posted November 11, 2009 Share Posted November 11, 2009 Russ is absolutely correct! Link to comment Share on other sites More sharing options...
zildac Posted November 11, 2009 Share Posted November 11, 2009 Hi Guys, I agree regarding the 32 bit address limitation, but PAE can overcome this albeit somewhat unelegantly. So in theory if MS did allow you to use more than 4GB than you could do so with 32 bit OSes. But yes it's a moot point pretty much these days. Regards, Ross. Link to comment Share on other sites More sharing options...
hendrik Posted November 11, 2009 Author Share Posted November 11, 2009 An operating system that is built on 32bit architecture can only use a 32bit string to reference any memory location. Which means a 32 bit memory address can only refer to a maximum of 4.2 billion unique locations, that equates to the 4GB address limit. Your question is really of moot point now mate as with Windows 7, all stand alone single user boxed versions ship with both 32 bit and 64 bit versions of the OS in the box on seperate DVD's. So you are not saving any money by sticking with 32 bit, the only real reason for not going to 64 bit in the past was lack of driver support, but in recent years 64 bit driver support is no longer an issue. Russ. Thanks Russ - particularly your last point. That I didn't know (I had asked on one of the forums whether, if I bought 32bit Win 7 I could unlock the 64bit version at extra cost. I'd read this somewhere!). I have Home Premium sitting on a shelf (Still using the RC) so opened it up - and Lo! 2 DVD's 32 and 64bit versions. Doh! So, high-jacking my own thread, is there ANY reason(s) why I shouldn't install the 64 bit version. Are there any sites out there listing apps etc for which 64bit drivers remain problematic? Link to comment Share on other sites More sharing options...
Russ White Posted November 11, 2009 Share Posted November 11, 2009 You would be hard pressed to find a bit of hardware today that did not have 64bit driver support, especially with the way 32 & 64 bit windows 7 are both being supplied together now. I recently built a new i7 rig for my father with Windows 7 64bit, and it was the easiest installation i have ever done. Russ. Link to comment Share on other sites More sharing options...
Dukester Posted November 12, 2009 Share Posted November 12, 2009 Umm, if you get an OEM version of W7 then you only get one version either 32 or 64bit not both from what I have seen. Anyone know if this is a dealer choice or mandated by MS? Link to comment Share on other sites More sharing options...
peterhayes Posted November 12, 2009 Share Posted November 12, 2009 Flinty It's an MS mandate to get Win 7 OEM you are meant to be a "system builder" and you get either 32-bit or 64-bit on the disc at a much cheaper price, but it is meant for that particular PC only. With regard to 32-bit and 64-bit PCs its nothing to do with the physical RAM onboard its all to do with the Virtual address space and Windows 32-bit can only access 4GB as said above whereas 64-bit PCs can access up to 16TB. You do not have to have the same amount of physical RAM onboard in order for the OS to address the full complement of the VAS. For example, you could put 16GB Physical RAM on a 32-bit OS but you would still only address 4GB of VAS and still have OOM issues in FSX due to the limits of a 32-bit OS. The beauty of a 64-bit system is that it manages virtual memory much better than a 32-bit OS that's why you are unlikely to see an OOM issue on a 64-bit system. Vista and Win 7 also handle video RAM much better than XP-32-bit. So although this link is quite correct it doesn't address the issue of a 32-bit limited VAS, and that's what causes problems in FSX not the amount of physical RAM that you have on board. Regards PeterH Link to comment Share on other sites More sharing options...
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