Discussion in 'Graphics Cards' started by Mussels, Apr 15, 2009.
GART memory allocation is only 256MB.
Must have read the first post wrong then.
Most excellent and apologies for a delayed response.
The performance gain is not really apparent in use, it is more of a functionality sort of issue.
like i paid extra for 8gb ram, why not spend a little more to obtain a 64bit version rather than waste 5/8th of it...
even for a home user when multi-tasking the speed up is immense with >3gb ram
this thread must not die!
its less about the maximum system ram of 4GB these days, and more about apps themselves needing more than 2GB.
look at all the crash bugs with skyrim solved by the LAA mod on 64 bit OS's - so common it actually got included as an official patch.
32 bit OS is dead for the PC gaming world.
Oh maybe that's it. Doubling. Did you see Black Panther's recent thread about GPU-Z monitoring? IIRC it was postulated that it seemed to be 768 over. But maybe it's doubled like you say and also maybe juts crossfire. Cause I too have it saying I am using more than I physically have.
So does that mean a 64-bit system with say 4GB ram running DX10 will have all 4GB of system RAM available since the above highlighted points wont be applicable on it ?
theoretically, if it was an LAA app yes.
i get excited when i see people post in this thread... and its always sad when its spam bots
I happened to find this thread completely by chance while doing my "homework" on the potential of a future Crossfire setup for my PC. Excellent write-up. Very informative.
However, what correlation would memory hole remapping have to the specific 32-bit addressing issue being discussed and how would it work out in practice? Would it be a viable solution for someone using 4 GB of RAM and two Radeon cards with 1 GB VRAM each who wants to stick with a 32-bit OS for whatever reason? My apologies if this has already been addressed, but I did skim through all 10 pages of comments before fielding this question.
In all technicality its a driver compatibility issue under 32bit register.
Address remapping (the "memory hole")
x86 chipsets that support more than 4 GB of RAM typically also support memory remapping (referred to in some BIOS setup screens as "memory hole remapping"). In this scheme, the BIOS detects the memory address conflict and in effect relocates the interfering RAM so that it may be addressed by the processor at a new physical address that does not conflict with MMIO. On the Intel side, this support once was limited to server chipsets; however, newer desktop chipsets like the Intel 955X and 965 and later support it as well. On the AMD side, the AMD K8 and later processors' built-in memory controller supported it from the beginning.
As the new physical addresses are above the 4 GB point, addressing this RAM does require that the operating system be able to use physical addresses larger than 232. This capability is provided by PAE. Note that there is not necessarily a requirement for the operating system to support more than 4 GB total of RAM, as the total RAM might be only 4 GB; it is just that a portion of it appears to the CPU at addresses in the range from 4 GB and up.
This form of the 3 GB barrier affects one generation of MacBooks, lasting 1 year (Core2Duo (Merom) – Nov 2006 to Oct 2007): the prior generation was limited to 2 GB, while later generations (Nov 2007–Oct 2009) allowed 4 GB by supporting PAE and memory hole remapping, and subsequent generations (late 2009 onwards) use 64-bit processors and support over 4 GB.
 Windows version dependencies
The final piece of the 3 GB barrier puzzle is a limit deliberately coded by Microsoft into the "non-server", or "client", x86 editions of Microsoft Windows: Windows XP, Windows Vista, and Windows 7. The 32-bit (x86) versions of these are able to operate x86 processors in PAE mode, and do so by default as long as the CPU present supports the NX bit. Nevertheless, these operating systems do not permit addressing of physical memory above the 4 GB address boundary. This is not an architectural limit; it is a limit imposed by Microsoft as a workaround for driver compatibility issues that were discovered during testing.
Thus, the "3 GB barrier" under x86 Windows "client" operating systems can therefore arise in two slightly different scenarios. In both, RAM near the 4 GB point conflicts with memory-mapped I/O space. Either the BIOS simply disables the conflicting RAM; or, the BIOS remaps the conflicting RAM to physical addresses above the 4 GB point, but x86 Windows client editions refuse to use physical addresses higher than that, even though they are running with PAE enabled. The conflicting RAM is therefore unavailable to the operating system whether it is remapped or not.
Thanks. After reading this am I correct in assuming that, in theory, memory hole remapping would not make one bit of difference and may actually leave one worse off?
No. the memory hole occurs because a reserved space is needed for every device in the system. Add more devices, and the amount of space available decreases per device. For multi-gpus, this extra space per GPU is not needed, as all data in each GPU's memory is duplicated anyway.
Remapping this space takes it from the 2GB spot(which makes a 2GB usable limit), and re-maps it to the upper end of the addressing limit. If it is not re-mapped, the space above 2GB would be unusable.
its just a compatibility share for 32bit os, but in all technicality the computers are limited with 32bit, 64bit does provide a better user experience and does boot fast
Fair enough. My concern was that, theoretically, the VRAM would be hoisted to a memory range the OS can't access, therefore rendering it unusuable. I guess I'm overthinking this.
Oh, I have no doubt that a 64-bit OS is the better solution. Nowadays, there's really not much of a practical choice between XP and 7 any more. Unfortunately, 7 is a bit of a hard sell for me due to potential issues with some of my hardware. I really don't want to have to perform voodoo to get the OS to recognize components simply because the drivers aren't signed.
What is your hardware?
yeah if you're in a situation where your hardware has no signed x64 drivers, you either need to replace that hardware, or stick with old hardware and software.
there comes a point where its not worth keeping the old stuff any more, and mixing with new hardware just wont work right due to OS requirements.
People, more ram the better. 64-Bit rocks all thanks to AMD. It's better to have both of these than not IMO.
I agree with you to a point . It is NOT all thanks to AMD is it however all thanks to Microsoft ! Lets try to keep this in perspective and not toss around the fanboy charm . AMD came out with the first 64 bit CPU yes Intel was slow to come out with one but they did have them in the P4 days as well .
Been on the 64 bit OS since windows XP ! Love it .
AMD made x86-64. intels solution previously was an entirely new OS with ZERO 32 and 16 bit compatibility - every single app had to be 64 bit.
AMD does deserve thanks there, as they did bring about operating systems that could run 32 and 64 bit at the same time.
I agree . I just did not want this to become a CPU war thread . AMD did force Intel to hand out a much more flexible alternative and that is the best thing . Having only 64 bit with out the advantage of running anything else was some thing consumers would have never liked and would have dealt Intel a very hard blow if not KILL them all together ! AMD did a great service in this area and continues to put Intel in check . But lets not get too grateful for AMD's hand in this it has also given programers a green light to just keep to the CODE ! In other words since 64 bit OS and CPU's can run 32 bit software just fine we still have yet to see games and other fine things use 64 bit to the full potential hence stagnating the game industry I mean hell even the browser industry is still on 32 bit slow to produce any 64 bit software . This is JMHO .
Nothing terribly exotic or archaic. My hardware RAID card (LSI/3Ware 9650SE) is my biggest concern, although Microsoft swears it's supported out of the box in 7. I'd like to take their word for it, but the horror stories of Vista have left me skeptical. Of lesser concern are my reservations about the functionality of 32-bit programs in 7 like DOSBox and such.
If someone's using dated hardware and it's preventing them from taking advantage of a 64-bit OS, they should definitely consider upgrading their components. However, if it results in them essentially building an entirely new system around the OS, budget constraints may kick in.
In my case, when I'm given the choice between buying another expensive RAID card or going with FakeRAID, the decision is not quite so practical.
Edited to Add: Thanks once again to all for the replies. They've helped me to understand this problem more in depth than I had previously.
Horror Stories from Vista are like cow pies in a pasture, and makes you smell just as bad. 7's nowhere near as bad as Vista was.
And implied insults are supposed to appeal to my logic and reasoning how, exactly?
You know, I could bring up the fact that 64-bit operating systems, once the domain of servers, were forced upon the public by Microsoft before they had reached their maturity as a desktop operating system for the average user... I could also bring up that there's no shortage of Linux users who'd love to comment on the absurdity of needing 2 GBs of ram (per MS) just for your operating system overhead, but I digress.
The fact of the matter is, yes. 7 is an arguably superior OS when compared to Vista. However, I also reserve my right to be skeptical of it because it's still relatively "new" to me and has "features" I'm not exactly sure I'd love. Thankfully, the civil and intelligent posts I've been reading are educating me in that regard.
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