ATI - Time to Switch?

[Super Six-Four 5]

I'm considering going with Nvidia after years of using ATI. Tired of poor performance in FS weather. Looking at an EVGA GTX 460 1G. Based on my specs, would this card make much of a difference in FS?i5 2500K 3.3GhzMSI P67A-C43ATI 4850 512Mb4G DDR3 1600 RAMWin XP 32Thanks for any help,Todd

[SpiritFlyer 987]

I'm considering going with Nvidia after years of using ATI. Tired of poor performance in FS weather. Looking at an EVGA GTX 460 1G. Based on my specs, would this card make much of a difference in FS?i5 2500K 3.3GhzMSI P67A-C43ATI 4850 512Mb4G DDR3 1600 RAMWin XP 32Thanks for any help,Todd

Hi Todd,It is amazing that you have been a member of AVSIM since 2002 and only posted 3 times (as of today)! Did your identity get lost in the AVSIM takedown? I take it you were Coneman with over 900 posts. Anyway, to answer your question, yes, you would benefit from changing to Nvidia with your setup, but I recommend you consider the 560 or above.Kind regards,

[Super Six-Four 5]

Thanks Stephen. Yes, I was able to recover my join date, but not post count...strange. I should have mentioned my budget is around $130-50, and the 460 has a rebate until the end of the month.Cheers,Todd

[SpiritFlyer 987]

Thanks Stephen. Yes, I was able to recover my join date, but not post count...strange. I should have mentioned my budget is around $130-50, and the 460 has a rebate until the end of the month.Cheers,Todd

Then the 460GTX will serve you well! I had both the 470GTX and the 480GTX and loved them both. The 460 GTX came afterward and enjoys a great reputation. Let us know what you decide!Kind regards,

[Bob Scott 7,716]

If you're going to keep your CPU below 4 GHz, the 460 is a good match.Just be aware that with a 32-bit OS, adding a 1GB video card may put you in OOM error purgatory, because the entire video RAM array takes address space away from the space available for OS/apps. So you're going to lose 512MB of address space currently available to your OS and apps with your 512MB 4870. If you use complex add-on aircraft and scenery, a 1 GB video card may push you over the brink there. Switching to a 64-bit OS will solve that if it does become a problem.

[dazz 69]

If you're going to keep your CPU below 4 GHz, the 460 is a good match.Just be aware that with a 32-bit OS, adding a 1GB video card may put you in OOM error purgatory, because the entire video RAM array takes address space away from the space available for OS/apps. So you're going to lose 512MB of address space currently available to your OS and apps with your 512MB 4870. If you use complex add-on aircraft and scenery, a 1 GB video card may push you over the brink there. Switching to a 64-bit OS will solve that if it does become a problem.

Can you please elaborate on this Bob? we had a thread discussing all this stuff recently and I seemed to conclude that since Vista the driver model does not keep a complete image of VRAM in VM, and that it keeps it in the application VAS, not the OS one, meaning that a 32b app in a 64b OS could still potentialy be affected (considering the 4GB VAS limit for apps in that scenario) although less likely than in a 32b OS with a 2GB VAS limit (3GB with userva + LAA tweaks)On the other hand, there was an article from microsoft linked in that thread. It said that DX9 apps running in WDDM still needed to keep a complete VRAM image in VAS due to compatibility issues with XPDM, but I know my FS9 doesn't take up the 1.5GB of VAS of my 480's Vram straight away. Maybe it's just the amount of VRAM in use what's mirrored to VM? I'll try monitoring VM / VRam at different AA settings and resolutions and see if there's a correlation

[Guest jahman]

If you're going to keep your CPU below 4 GHz, the 460 is a good match.Just be aware that with a 32-bit OS, adding a 1GB video card may put you in OOM error purgatory, because the entire video RAM array takes address space away from the space available for OS/apps. So you're going to lose 512MB of address space currently available to your OS and apps with your 512MB 4870. If you use complex add-on aircraft and scenery, a 1 GB video card may push you over the brink there. Switching to a 64-bit OS will solve that if it does become a problem.

Bob,Only a small window is used to pass data from RAM to VRAM, but I have never been able to find ut the size of that window, and whether that size is variable to accommodate video cards with larger VRAM.Cheers,- jahman.

[Bob Scott 7,716]

Bob,Only a small window is used to pass data from RAM to VRAM, but I have never been able to find ut the size of that window, and whether that size is variable to accommodate video cards with larger VRAM.Cheers,- jahman.

The OP lists Win XP 32 as his OS, so his total available virtual address space is 4GB.This isn't about passing data from RAM to VRAM, nor maintaining a VRAM page image in RAM, but it's the fact that the OS at boot does hardware address mapping of the entire VRAM memory space, meaning that with a 1 GB card in a 32 bit OS, fully 25% of the available 4GB of address space is assigned for use to access the VRAM and thereafter blocked from use by system RAM. In a 64-bit OS there are 8TB of available VAS, and though that same hardware address mapping also occurs, the 1GB of reserved VAS in this example is located at addresses above the 4GB boundary, so it doesn't affect a 32-bit app's available VAS.This is a separate issue from buffering the VRAM image in the app's VAS.

[Bob Scott 7,716]

Can you please elaborate on this Bob? we had a thread discussing all this stuff recently and I seemed to conclude that since Vista the driver model does not keep a complete image of VRAM in VM, and that it keeps it in the application VAS, not the OS one, meaning that a 32b app in a 64b OS could still potentialy be affected (considering the 4GB VAS limit for apps in that scenario) although less likely than in a 32b OS with a 2GB VAS limit (3GB with userva + LAA tweaks)On the other hand, there was an article from microsoft linked in that thread. It said that DX9 apps running in WDDM still needed to keep a complete VRAM image in VAS due to compatibility issues with XPDM, but I know my FS9 doesn't take up the 1.5GB of VAS of my 480's Vram straight away. Maybe it's just the amount of VRAM in use what's mirrored to VM? I'll try monitoring VM / VRam at different AA settings and resolutions and see if there's a correlation

OK, first the OP is using WinXP 32, so the Vista and beyond issue is moot here.But that said, I think we're confusing the term "VRAM" with the video frame buffer--VRAM is the actual array of physical RAM mounted on the video card, and the frame buffer is a data structure that's used by the device driver to store the commands being sent to the video card to draw a frame. IIRC, the image that DX9 apps keep in application VAS should be of the frame buffer, not the entire VRAM array (and the frame buffer is much smaller than total available VRAM). Much of the VRAM is used by the GPU doing its own thing processing AA/AF/Gamma enhancements, and that data is never seen/passed to the app as it remains internal to the video card.

[Guest jahman]

Bob, I really don't think VRAM is part of the 4 GBy VAS (except for the window): A 2 GBy card would be a show-stopper for a 32-bit system! (After OS and VRAM, no VAS left for the game!) Heck, there's even 3 GBy video cards out there from nVidia.Cheers,- jahman.

[dazz 69]

Bob, I really don't think VRAM is part of the 4 GBy VAS (except for the window): A 2 GBy card would be a show-stopper for a 32-bit system! (After OS and VRAM, no VAS left for the game!) Heck, there's even 3 GBy video cards out there from nVidia.Cheers,- jahman.

We both missunderstood his point (sorry about that Bob), he's talking about VRAM to physical RAM mapping at boot time, not VMGonna try my 1.5GB GPU on a 32b Win 7

[Bob Scott 7,716]

Bob, I really don't think VRAM is part of the 4 GBy VAS (except for the window): A 2 GBy card would be a show-stopper for a 32-bit system! (After OS and VRAM, no VAS left for the game!) Heck, there's even 3 GBy video cards out there from nVidia.Cheers,- jahman.

I'm starting to think the exact methodology isn't completely understood by anyone except the programmers at MS.I did a small experiment today...I loaded WinXP 32 on my secondary PC with a GTX8800 and 768MB of RAM--Windows reported 3.5 GB of RAM available to it. I swapped it for a 2GB GTX285, and XP reports 2.75GB of RAM available to it.So the impact to VAS isn't 1:1 when going from 768MB to 2048MB of VRAM, but the VAS footprint does scale up significantly with increased physical VRAM. Perhaps the amount of hardware-mapped VRAM is capped at some limit, or a block is reserved based on some portion of the physical VRAM.But for the OP, I remain certain that going from a 512MB to a 1GB video card in XP32 will reduce the amount of available VAS, and if running complex add-ons and sceneries, may well cause OOM errors to pop up where they did not before.

[Super Six-Four 5]

Thanks for all the info guys...most of it did a flyby I'll just be prepared for OOM errors until I upgrade the OS.Cheers,Todd

[dazz 69]

I tried my GTX480 in a fresh Win 7 32b install and the available amount of RAM is 3.4GBWin 7 is not XP though.I searched the web and found a game devs forum where one of them said that it's not necessary to map the whole VRAM to physical RAM (32b OS), and these results seem to confirm that.Anyway, it's definitely a good idea to switch to a 64b OS (Windows 7 much better) especially if it's for FSX. It's very easy to go 2GB+ in FSX

[Guest jahman]

I'm starting to think the exact methodology isn't completely understood by anyone except the programmers at MS.I did a small experiment today...I loaded WinXP 32 on my secondary PC with a GTX8800 and 768MB of RAM--Windows reported 3.5 GB of RAM available to it. I swapped it for a 2GB GTX285, and XP reports 2.75GB of RAM available to it.So the impact to VAS isn't 1:1 when going from 768MB to 2048MB of VRAM, but the VAS footprint does scale up significantly with increased physical VRAM. Perhaps the amount of hardware-mapped VRAM is capped at some limit, or a block is reserved based on some portion of the physical VRAM.But for the OP, I remain certain that going from a 512MB to a 1GB video card in XP32 will reduce the amount of available VAS, and if running complex add-ons and sceneries, may well cause OOM errors to pop up where they did not before.

That makes sense: As you increase VRAM, the size of the window is automatically increased as well, thus decreasing VAS available to apps.Cheers,- Jahman.