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post #31 of 33
Quote:
Originally Posted by Paradigm Shifter View Post
Heh, no worries, you got me wondering whether I'd read it wrong.
Haha, I swear I'm not as misinformed as that post would lead you to believe! Check my post history

Quote:
I hope that equates to a similarly low price in the UK. Then they might be affordable. But the prices of the 1.5GB GTX580s have to drop first here. Cheapest I remember when I checked today was £390 or something.
Hopefully. Palit has had the market cornered on high VRAM fermi cards for a while now.
post #32 of 33
Quote:
Originally Posted by Paradigm Shifter View Post
I do need to see if I can get my hands on a pair of 6950s/6970s to test VRAM usage with. I remember back in the X1900-era that ATi cards were more VRAM efficient; whether that is still the case or not, I have no idea. I haven't touched ATi/AMD since the 4800 series.
Lot of great input on this thread PS

Head-up on the ATI/AMD cards: Unless things have changed in the last 8 months since I had my 5850's, AMD still haven't modified their driver API to expose vram usage in Vista/7 like nVidia was kind enough to do a while back. So you can't see vram usage numbers on AMD cards post-XP.

Quote:
Originally Posted by Zmanster View Post
That's interesting. If this is true, then adding additional system RAM, buying another 470 and then going with three 120Hz monitors in "Nvivia Surround" might work @ 5760X1080p resolution, playing games like Cryisis 2 at frame rates above 30....I hope?!?!
You should probably start up your own thread for these questions

Quote:
Originally Posted by Paradigm Shifter View Post
It's nVidia tech from years ago, which they tended to use on laptop chipsets and on the low-end desktop GPUs so they could give it, say, 64-256MB of VRAM on the card, then get it to use system RAM if it needed more. Exactly like ATi's HyperMemory. To be honest, the idea wasn't great, it wasn't terribly well thought out and as a result it ended up fairly useless.

Some reading on TurboCache:

http://www.nvidia.co.uk/page/turbocache.html

http://en.wikipedia.org/wiki/TurboCache

http://www.hardwaresecrets.com/article/124



But it's the closest example I can think of that mirrors roughly what I'm seeing in system RAM usage.
To the best of my knowledge, it's always been the case that any overflow of vram usage beyond what's physically on the card will spill over into using the system ram. I base this assumption on the following:

1) If this couldn't happen, it seems like rather than the fps tanking as it currently does (and as you would expect, due to the massive drop in effective bandwidth inherent in using system memory in this way), your game would simply crash when it ran out of free memory to address.

2) Back when I used to play Stalker SoC on a 320MB card in XP, I'd regularly see 'video memory' usage (displayed, as it was done back in the day, via the Rivatuner OSD) on the order of 500MB.

My understanding (which could be wrong) on this 2nd point goes like this: on XP, Rivatuner would display a usage number provided by the Windows API directly.

The Windows API could account for and expose a 'true total' value, wherein it combined the usage of the card's local physical memory + any 'overflow' usage (i.e. what's happening in system RAM) into a single 'video memory' usage value for apps like RT to display via OSD.

Hence: my seeing 500MB of video memory usage on a 320MB card (and of course the perf became a slide-showy mess when such usage occurred) back in the XP days.

However, in Vista/7, the Windows API no longer exposes a 'video memory' usage value, and what we see in this regard now comes from the driver API. I believe this is strictly a 'vram' usage value, and cannot account for/expose 'video memory' usage in excess of what's physically on the card.

So, system ram 'requisition' can still happen as needed, just like it did w/XP, but you can no longer see it accounted for in Vista/7 using a single tool like you could before.
Edited by brettjv - 4/14/11 at 2:34pm
    
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post #33 of 33
Quote:
Originally Posted by Booty Warrior View Post
Haha, I swear I'm not as misinformed as that post would lead you to believe! Check my post history
I'm neck deep in the whole Surround/EyeFinity thing, although I've got more experience with Surround, so try to help out where I can.

Quote:
Originally Posted by Booty Warrior View Post
Hopefully. Palit has had the market cornered on high VRAM fermi cards for a while now.
Aye; Palit/Gainward are the same company... and the only 'double VRAM' cards around. 'Tis very annoying.

Only other options are Quadro cards (as I mentioned) and they require selling limbs/vital organs to pay for 'em.

Quote:
Originally Posted by brettjv View Post
Lot of great input on this thread PS
Thanks, it's pure chance I saw it actually - I've not had the time to really look at OCN for weeks.

Quote:
Originally Posted by brettjv View Post
Head-up on the ATI/AMD cards: Unless things have changed in the last 8 months since I had my 5850's, AMD still haven't modified their driver API to expose vram usage in Vista/7 like nVidia was kind enough to do a while back. So you can't see vram usage numbers on AMD cards post-XP.
Hm, that's a shame. Thanks for the heads up on that, I'd have been steaming had I found out the hard way!

Quote:
Originally Posted by brettjv View Post
To the best of my knowledge, it's always been the case that any overflow of vram usage beyond what's physically on the card will spill over into using the system ram. I base this assumption on the following:

1) If this couldn't happen, it seems like rather than the fps tanking as it currently does (and as you would expect, due to the massive drop in effective bandwidth inherent in using system memory in this way), your game would simply crash when it ran out of free memory to address.

2) Back when I used to play Stalker SoC on a 320MB card in XP, I'd regularly see vram usage (displayed, as it was done back in the day, via the Rivatuner OSD) on the order of 500MB.

My understanding (which could be wrong) on this 2nd point goes like this: on XP, Rivatuner could display a vram usage number provided by the Windows API directly. The Windows API could account for and expose a 'true total' value, wherein it combined the usage of the card's local physical memory + any 'overflow' usage (i.e. what's happening in system RAM) into a single value for RT or the like to display via OSD.

Hence: my seeing 500MB of video memory usage on a 320MB card (and of course the perf became a slide-showy mess when such usage occurred) back in the XP days.

However, in Vista/7, the Windows API no longer exposes a true 'video memory' usage value. What we see in this regard now comes from the driver API, which is strictly a 'vram' usage value, and cannot account for/expose a 'video memory' usage number in excess of what's physically on the card.

So, system ram 'requisition' can still happen as needed, just like it did w/XP, but you can no longer see it accounted for in Vista/7 using a single tool like you could before.
Not sure how XP handles it, but you've not said anything that looks wrong from what I've been given to understand.

However, the idea of TurboCache/HyperMemory was something nVidia/ATi came up with in the GeForce 6/X1x00 series days, but made a standardised feature when the unified architecture of the GeForce 8/HD2x00 series arrived on the scene with DX10. I never saw VRAM number exceeding what was on my cards with a 6800GT or 7900GTO. I don't remember seeing any 'exceeding VRAM' numbers on an 8800GT, but I never really pushed that card that hard.

I'm fairly sure the reason the framerate drops to <1fps on a heavily VRAM limited system is because it's actually trying to swap to pagefile. It's a cascade effect; runs out of VRAM, hits the system RAM, runs out of system RAM, hits up the pagefile. This hypothesis is supported by watching pagefile size (windows automanage) and how the effect is a little less pronounced with 12GB of RAM over 6GB. What's bandwidth on a GPU to VRAM? 60GB/s? Then to system RAM... 10GB/s? Then to HDD... 150MB/s... maybe? And that doesn't include latency, which would go from nanoseconds, to tens of nanoseconds to milliseconds on a HDD...
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Aoi
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Midori
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Core i7 920 D0 Gigabyte G1.Killer Guerilla GTX670 4GB SLI 24GB Corsair Vengeance 
Hard DriveHard DriveOptical DriveCooling
WD Velociraptor Samsung F1 Blu-ray XL Corsair H70 
OSMonitorMonitorMonitor
Windows 7 Professional x64 Dell 2405FPW Dell U2410 Dell 2405FPW 
MonitorKeyboardPowerCase
Dell U2311H Microsoft Sidewinder X4 Silverstone Strider 1kw Corsair 700D 
MouseMouse PadAudioOther
Logitech G500 Ozone XL Integrated Logitech G13 
CPUMotherboardGraphicsRAM
Core i5 3570K Asus P8Z77-M Pro nVidia GTX680 Corsair Vengeance LP 16GB 
Hard DriveOptical DriveOSOS
WD Velociraptor 600GB Samsung DVD+RW Windows 7 Home Premium x64 Ubuntu Server Customised 
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